1. Unless the complete case file / record of the Registration / issued Certificate which was done in USA with a german fiancee is checked no concrete opinion be given if the process of marriage and the so called registration / certificate is itself valid or not in India!
2. The Marriage Certificate issued by the concerned Authority in USA is just a proof of marriage and if that is checked one can state about the validity of the marriage process only !
3. As such a Civil Marriage between two person solemnized anywhere in the world according to any country's matrimonial law unless that forbid marriage between its citizen and any foreigner or it provides for only certain class of people in that country, it is valid marriage duly recognised anywhere in the world.
4. Any marriage taking place in a foreign country according to the matrimonial laws of that country will not give Jurisdiction to Indian court to adjudicate on any dispute between the parties unless that foreign marriage is either Registered under the Indian Foreign Marriage Act or Certified under this Act or is Registered under the Special Marriage Act, 1954 here in Indian soils.