In the original "Back to the Future" movie, Doc has his famous "1.21 Gigawatts" scene. But I noticed today that the French version actually is translated "2,21 Gigawatts" (deux virgule vingt et un Gigawatts).
I have two minor arguments for lip syncing : In the French version doc actually pronounce "Gigowatts", so exactitude was not a main worry for the translation team. Also, the French wikipedia page mention that it was a lip syncing problem, but the cited sources make no mention of this. So no definitive proof.
in short : Was this change made solely for lip syncing ?
EDIT : To be clear, I am talking about the change of value from 1.21 to 2.21. The change of the dot to the comma is normal in French