No: the law does not require a company, and commercial property in Germany can be bought by an individual or by a foreign company. A German limited-liability company (GmbH) is a choice, not an obligation, but in our experience most foreign buyers of single properties worth €3–20 million prefer it. For limited liability, access to bank loans and simpler inheritance, they give up an untaxed sale after ten years of ownership.
What to check:
• the structure — before the letter of intent, with a tax calculation for Germany and your country of residence;
• the GmbH's registration in the commercial register before the purchase agreement is signed;
• a release of the managing director from the restrictions of § 181 BGB in the articles, if the director personally signs the shareholder loan;
• the entry of the beneficial owners in the Transparency Register (Transparenzregister);
• the lease — for compatibility with the extended reduction of trade tax.