Resyncing a project to a different language

I made a tutorial video in Motion 4 that was basically synced to an audio file of a narrator explaining in english how to use a certain product. Now the client wants me to sync the same video to an audio file of a french version of the same tutorial. Now I have to resync the entire project to fit the french audio. And well, it's quite a mess. moving all these keyframes and objects around. My question is, Is there some kind of shortcut to do this process that you may know of or some tips you have for doing that kind of work?
thanks!