Iranian authorities are holding a German man and Frenchman whose boat reportedly strayed into that country's territorial waters during a vacation trip more than three weeks ago, the German government said Thursday. German and French diplomats in Teheran were working to secure the men's release, said a Foreign Ministry spokesman who is not permitted to give his name. According to a report in the Rheinpfalz newspaper, the 52-year-old German had been on vacation with his wife and a French friend in the United Arab Emirates. The two men were arrested on Nov. 29 during a fishing trip in the Straits of Hormuz apparently after straying into Iranian waters, it said. On Dec. 13, the Foreign Ministry called in the legal attache from the Iranian Embassy in Berlin to insist that German diplomats be allowed access to their citizen, the spokesman said. The man, whom German officials have reached by telephone, was in good health and had not been mistreated during questioning, the spokesman said.