Unless there is someone from Capgemini in that specific practice I don't think you're going to get an answer.
What is Capgemini offering you that makes you want to leave your current role?
If you're going to be promoted to Manager in the near future will this give you the same salary uplift etc that moving to Capgemini now will?
I personally think that the answer to these two questions should be more important than whether or not you'll be called a Manager in Capgemini.
I think you can get an answer from Capgemini on your specific question - either ask them directly or be more subtle and ask what the promotion/advancement opportunities are and what the next couple of levels would look like.
If it goes like this:
Title - local equivalent grade
Snr Consultant - Manager
Manager - Snr Manager
Snr Manager - Director
Director - Partner
then that's one thing but it could also go like this:
Snr Consultant - Manager
Manager - Manager
Snr Manager - Snr Manager
Director - Director
because of some strange career level balancing that happened as a result of expansion or whatever.
Hope my Monday morning rambling is of some help.