Is it possible for a Schengen visa holder expiring soon to get married to a German citizen in Germany without having to leave and reentering the country? In any case, what will be the problems one will face if his visa expired in this situtation?
- Foreigners who want to marry in Germany have to show documents from their homeland that they can legally marry, e.g. that there are no previous marriages or that they are properly divorced. Getting those documents on short notice could be difficult.
- Marriages for the sole purpose of gaining immigration status (Scheinehe) may be dissolved by the courts, using them to gain immigration permits may be punishable for both partners. On the other hand, genuine marriages are protected by the constitution and laws, the two partners have a right to live together as a family. In a case like yours, questions would be raised. Can you answer them?
- People who are getting married have to prove their identity to the registrar. They have to show their papers.
Summarized, I don't think your idea is practical. In the few cases I know personally, the non-EU partner had always applied for a temporary residency permit first. This gave the time for the bureaucratic steps and gave the family time to apply for tourist visa for the celebrations.