Do I need a transit visa for Germany? [duplicate]

You don't need a transit visa because it won't help you. You need a visitor visa because you will enter the Schengen zone.

Your flight from Frankfurt to Munich will almost certainly be classed as a domestic flight.* Thus you must enter the Schengen area in Frankfurt and then exit the Schengen area in Munich. This will require a visitor visa, not just a transit visa, since you are entering the Schengen area to board the domestic flight.

The key difference between transiting between two international flights and what you are doing is that, even if you do not intend to leave the two airports, there is nothing stopping you from doing so. Once you mix with the domestic passengers, you could simply exit the airport. So the authorities must trust you not to abscond. This trust requires a visitor visa. A transit visa entails a lower level of trust, as transiting does not give you such an easy opportunity to abscond.

With only a transit visa (or no visa), you will not be allowed past border control in order to get to the domestic flight. Indeed, you will probably never make it to Frankfurt without an appropriate visa, since the airline will not check you in in Bangalore without one.

*_{^{Very rarely, a domestic flight will be classed as an international flight. (I've had this once.) This is convenient for travelers like you or for people who prefer to clear customs at their final destination. But it is inconvenient for domestic travelers who would need to go through passport control twice. Check with your airline if you believe this is the case for your flight from Frankfurt to Munich.}}