# Requests for Information from the Hauptzollamt Erfurt to Clients of Polish Subcontractors: Response Forms, Duties and Risks > German clients should carefully obtain legal review of requests from the Hauptzollamt Erfurt concerning Polish subcontractors. Source: https://www.mtrlegal.com/en/requests-information-hauptzollamt-erfurt-polish-subcontractors/ · Language: en · Updated: 2026-10-22 --- ## Requests for information from the Hauptzollamt Erfurt in connection with Polish subcontractors The Hauptzollamt Erfurt (Main Customs Office Erfurt), Finanzkontrolle Schwarzarbeit (Financial Control of Undeclared Work) at the Gera site, is conducting investigations on behalf of the Staatsanwaltschaft Mühlhausen (Public Prosecutor’s Office Mühlhausen) against several Polish companies. According to the underlying allegations, these companies are said in particular to have deployed workers from Ukraine, Belarus and Georgia in Germany without the required work permits being in place. In some cases, forged EU identity documents are alleged to have been used. In addition, there is an allegation that [social security contributions were not](https://www.mtrlegal.com/regions/gera/wirtschaftsstrafrecht/) paid in the legally owed amount. Investigations are being conducted, among other things, into possible violations of the Strafgesetzbuch (StGB, German Criminal Code), the Aufenthaltsgesetz (AufenthG, Residence Act) and [the Schwarzarbeitsbekämpfungsgesetz (SchwarzArbG, Act to Combat Undeclared Work)](https://www.mtrlegal.com/regions/chemnitz/schwarzarbeit/). These investigations are ongoing proceedings. The presumption of innocence applies to all accused persons; the allegations made are not equivalent to a final and binding finding. German clients that have worked with the Polish companies concerned are receiving requests for information from the Hauptzollamt Erfurt in this context. These letters frequently include a response form and provide for a written hearing. Before responding, a formal review of the letter is advisable. According to a description by the data protection service provider dids regarding requests for information from investigation and law enforcement authorities, it should be checked whether the requesting authority, the case reference, the purpose of the request and the specific legal basis are stated; information by telephone should be avoided. At the same time, according to this source, a data protection law authorisation to transmit data does not, in itself, establish an obligation on the company to provide information. ## Background to the investigations in the construction and services sector ### Search measures by the Staatsanwaltschaft Mühlhausen and the Hauptzollamt Erfurt In recent years, the Staatsanwaltschaft Mühlhausen and the Hauptzollamt Erfurt have carried out nationwide measures in several proceedings. On 2 December 2025, according to official information, around 200 customs officers searched 13 properties, including residential and business premises as well as construction sites in Thuringia, Hamburg, Hesse and Lower Saxony. The measures were directed against three accused persons aged 39, 44 and 64 on suspicion of withholding social security contributions and tax evasion. Investigations are being conducted against two further accused persons aged 40 and 36 on suspicion of aiding and abetting. According to the published information, the focus of the proceedings was in northern Thuringia. In this complex, the alleged loss was estimated by the investigative authorities at more than two million euros; according to the investigative authorities, companies involved are said to have exchanged sham invoices with one another in order to conceal the conduct. Another search measure followed on 9 March 2026. More than 160 customs officers, acting on behalf of the Staatsanwaltschaft Mühlhausen, searched 16 residential and business premises in Thuringia, Berlin, Bremen, Hamburg, Lower Saxony, Saxony and Saxony-Anhalt. In these proceedings, the allegations are directed against a 36-year-old main accused from Weimar; investigations are being conducted against 21 further accused persons aged between 26 and 67 for aiding and abetting. The estimated loss was stated to be more than 1.2 million euros. According to the customs press release on this measure, the investigations in the construction sector focus in particular on the exchange of sham invoices between companies involved and losses in the millions. Requests for information to German clients are regularly part of clarifying service and payment relationships within such procedural complexes. For affected companies, this means that the request should not be viewed in isolation, but rather in the context of an investigation that is already at an advanced stage. ### Nationwide activities of the Hauptzollamt Erfurt In proceedings of this kind, the Hauptzollamt Erfurt does not act only regionally. On 23 September 2026, 22 officers of the Hauptzollamt Erfurt, together with the Bundespolizei (Federal Police), searched three business and private premises in Hamminkeln-Dingden in North Rhine-Westphalia. The background was investigations against the owners of a company in Poland on suspicion of undeclared work. Investigations were also conducted across locations in another proceeding: on 7 October 2026, the Hauptzollamt Erfurt, acting on behalf of the Staatsanwaltschaft Chemnitz (Public Prosecutor’s Office Chemnitz), searched six properties in the Vogtland district and in northern Germany. The loss estimated there was put at around five million euros. In comparable proceedings, investigative authorities base the allegation, among other things, on the assertion that German parties effectively acted as employers of the foreign workers and deliberately circumvented the obligation to pay social security contributions in Germany. The posting certificate issued by the foreign social security institution may also play a role in this context. ## Content of the letters to German clients ### Response form and extensive requests for documents The recipients of the letters are regularly addressed as witnesses. Nevertheless, in terms of their content, the questions may go beyond merely clarifying peripheral matters. From the perspective of the investigative authorities, it may be relevant whether a deployment described as a contract for work was in fact structured as concealed temporary agency work. The requests for information often demand extensive documents and information, such as: - time sheets and working time records, - lists of names of the persons deployed, - copies of identity documents, - contracts with the Polish companies, - invoices and payment documents, - complete email correspondence, - information on intermediaries or interposed persons, - information on the contractual form, - details of the hourly charge-out rate, - information on whether representatives of the client have already been on site in Poland. According to the described facts, the deadlines set are regularly only a few weeks. For companies, this can entail considerable organisational effort, especially if projects ran over longer periods or several subcontractors were involved. ### Witness status and potential own exposure Formally, the German clients are treated as witnesses in these letters. However, this classification does not rule out that individual questions are aimed at circumstances that may also be relevant to possible liability of their own. This applies in particular to situations in which the actual course of cooperation differs from the contractual designation. For the legal assessment, it must first be clarified in what capacity and by which body a company is being contacted. A distinction must be made between a summons or request from the public prosecutor’s office under § 161a StPO (German Code of Criminal Procedure), a summons by customs investigators on a specific instruction from the public prosecutor’s office under § 163 para. 3 StPO, and a request for information by the Finanzkontrolle Schwarzarbeit in audit proceedings under § 5 SchwarzArbG. This classification determines which duties to appear, testify or provide information exist and which rights of refusal apply; by contrast, the status of an accused person entails a comprehensive right to remain silent. The focus may be on distinguishing between a genuine contract for work and concealed temporary agency work. What matters is not merely the heading of the contract, but the actual performance of the cooperation. If a contract for work is ultimately assessed as concealed temporary agency work, a connected chain of consequences applies: the supply contract is invalid under § 9 para. 1 no. 1a AÜG (German Temporary Agency Work Act), according to the presentation by the IHK Pfalz (Chamber of Industry and Commerce Palatinate) an employment relationship with the hirer is generally deemed to exist, and under § 10 para. 3 AÜG the hirer is liable alongside the supplier for social security contributions. For clients, this may result in liability that economically exceeds the value of the originally commissioned service. ## Duties to cooperate and provide information to customs ### § 5 SchwarzArbG as the basis for cooperation Under § 5 para. 1 SchwarzArbG, duties to tolerate and cooperate expressly also apply to clients of services or works, hirers and third parties. Upon request by the customs administration authorities, information must be provided in writing, electronically or orally at the authority’s offices. The customs administration may require oral information at its offices in particular if no written information has been provided despite a request. The duty to cooperate is therefore not limited to the employer directly suspected, but may also cover companies that have used services. § 5 para. 1 sentence 2 SchwarzArbG also contains a limitation: information may be refused to the extent that it would expose the obliged person or a relative within the meaning of § 15 AO (German Fiscal Code) to the risk of prosecution for a criminal offence or an administrative offence. ### Witness duties under the Strafprozessordnung In addition to the powers under the Schwarzarbeitsbekämpfungsgesetz, rules of criminal procedure may be relevant. Under § 161a para. 1 StPO, witnesses are obliged to appear when summoned by the public prosecutor’s office and to testify on the matter. In the event of an unjustified refusal, the public prosecutor’s office has the measures provided for in §§ 51, 70 and 77 StPO at its disposal; the imposition of detention remains reserved to the court. Since the revision of § 163 para. 3 StPO, a duty of witnesses to appear may also exist in the case of a summons by investigators if it is based on a specific instruction from the public prosecutor’s office. § 55 para. 1 StPO gives every witness the right to refuse to answer individual questions if answering them would expose the witness or a relative to the risk of prosecution for a criminal offence or an administrative offence. This right relates to individual questions and does not replace all cooperation on a blanket basis. ## Legal risks for clients ### Subcontractor liability in the construction sector Special liability risks exist for companies in the construction sector. Under [§ 28e para. 3a SGB IV (German Social Code, Book IV)](https://www.bundestag.de/resource/blob/656692/e0a3b5fe100e96c300da29aa7dee7fec/WD-6-060-19-pdf-data.pdf), a construction-sector contractor that commissions another contractor to provide construction services within the meaning of § 101 para. 2 SGB III (German Social Code, Book III) is liable for the subcontractor’s contribution obligations in the same way as a directly liable guarantor. This rule has applied since 1 August 2002. In addition, § 13 MiLoG (German Minimum Wage Act) orders the corresponding application of § 14 AEntG (German Posted Workers Act). This results in strict guarantor liability of the client for minimum wage claims of employees employed by subcontractors. The Bundesverfassungsgericht (Federal Constitutional Court) approved § 14 AEntG by decision of 20 March 2007. According to the status report of the Wissenschaftliche Dienste des Deutschen Bundestages (Research Services of the German Bundestag) on subcontractor liability, this liability covers not only the direct contractual partner, but extends to the subcontractors brought in along the chain. Since neither fault nor knowledge of the conditions at the subcontractor is required, this is where the client’s actual economic risk lies: claims may be asserted without any misconduct of the client itself being alleged. This applies in parallel to contributions under § 28e para. 3a et seq. SGB IV and to minimum wage claims under § 13 MiLoG in conjunction with § 14 AEntG. ### Remuneration claims under § 98a AufenthG Under [§ 98a para. 1 AufenthG](https://www.gesetze-im-internet.de/aufenthg_2004/__98a.html), an employer that has employed a foreign national without the required permit or authorisation to engage in employment is obliged to pay the agreed remuneration. In this respect, an employment period of three months is presumed. Liability under § 98a AufenthG may also extend to contractors that commission another contractor to provide works or services. They are liable for the fulfilment of that contractor’s remuneration obligations. ### Concealed temporary agency work and AÜG risks If a deployment described as a contract for work is in fact carried out as temporary agency work and the labelling and specific identification of the agency worker are lacking, the supply is unlawful under § 9 para. 1 no. 1a AÜG. Since the 2017 reform of the AÜG, a so-called reserve permit no longer protects against these consequences. According to Haufe’s presentation on the reform of temporary agency work, a lawful supply requires that the contract be expressly designated as temporary agency work and that the supplied person be specifically named before the start of the supply. It is precisely these labelling and specification duties that are a typical weak point in subcontractor agreements, because contracts are drafted as contracts for work or services and the persons deployed are not identified by name. Breaches of these requirements may also be subject to fines under § 16 para. 1 AÜG. In the case of concealed temporary agency work, an employment relationship with the hirer generally arises. This does not apply if the employee submits a timely declaration of adherence, which must be presented in person to the Agentur für Arbeit (Employment Agency) and countersigned, and must be forwarded to the supplier or hirer no later than the third day thereafter, § 9 para. 2 AÜG. For the hirer, this may result in significant social security and tax law risks. Under § 10 para. 3 AÜG, the hirer is liable for contributions alongside the supplier. Breaches of disclosure and specification duties may be punished with an administrative fine of up to 30,000 euros under § 16 para. 1 AÜG. ## Significance of the investigations for companies ### Intensity of audits by the Finanzkontrolle Schwarzarbeit In 2023, the Finanzkontrolle Schwarzarbeit of the Hauptzollamt Erfurt audited a total of 2,069 employers in Thuringia and south-west Saxony. Of these, 1,185 audits related to Thuringia and 884 to south-west Saxony. These figures show that the monitoring of working conditions, social security obligations and employment structures is of considerable practical importance. Criminal enforcement practice within the jurisdiction of the Hauptzollamt Erfurt must also be taken into account. In September 2026, the Amtsgericht Gera (Local Court of Gera) convicted a construction contractor of withholding social security contributions and tax evasion and imposed a suspended custodial sentence; whether this judgment is final and binding is not known. Where a judgment is not expressly described as final and binding, this should not automatically be equated with proceedings that have been conclusively completed. ### Significance of actual contractual performance When classifying subcontractor relationships, the written agreement alone is not decisive. How the cooperation was actually organised is also relevant. In particular, instruction structures, deployment planning, working time recording, integration into operational processes and actual responsibility for the personnel deployed may be relevant. If investigative authorities request documents such as time sheets, email correspondence, lists of names and information on intermediaries, this may indicate that they wish to reconstruct the actual performance of the contractual relationship. For clients, this may create an interface between witness status, duties to cooperate and possible risks of their own. ## Classification of duties in the event of a request for information A request for information from the Hauptzollamt Erfurt may affect companies on several levels. On the one hand, statutory duties to cooperate exist. On the other hand, rights to refuse information may apply insofar as there is a risk of self-incrimination or incrimination of close relatives within the meaning of the relevant provisions. In the case of official requests for information, the following points are regularly important: - which authority sent the letter, - which case reference is stated, - what purpose of the request is given, - which legal basis the request relies on, - whether written, electronic or oral information is requested, - whether a deadline has been set, - whether documents or factual statements are requested. A data protection law authorisation to transmit data is not automatically equivalent to an independent duty to provide information. Likewise, information provided by telephone may create particular uncertainties because its content, context and scope may later be assessed differently. ## Professional advice on white-collar criminal law issues Requests for information from the Hauptzollamt Erfurt in connection with Polish subcontractors may have far-reaching significance for clients, even if they are initially addressed formally as witnesses. The interplay of duties to cooperate, rights to refuse information, subcontractor liability, social security obligations and possible AÜG consequences requires careful legal classification of the specific individual case. MTR Legal Rechtsanwälte supports companies, investors and high-net-worth private individuals in white-collar criminal proceedings as well as at the interfaces with commercial, corporate, tax and employment law. Anyone confronted with a request for information, a response form or investigative measures in connection with subcontractor structures can find further information under [legal advice in white-collar criminal law](https://www.mtrlegal.com/rechtsberatung/wirtschaftsstrafrecht/).