Esta resposta se aplica:
No, you do not need a visa for going from the US to India via Frankfurt airport (or vice versa), as long as you stay in the transit area and have a connection in less than 12 hours. Lufthansa, emphasis mine:
Indian nationals can Transit without Visa via FRA or MUC if holding a valid visa for the destination and a valid Visa for any of the following countries: Bulgaria, Canada, Cyprus, Ireland, Japan, Liechtenstein, Romania, UK and USA (the approval notice I-797 is not valid document for visa free airport transit).
O site do consulado alemão em Kolkata também confirma isso.