Yes, the Egyptian collection, including the Rosetta stone, should be returned to France.
(Under no circumstance should it be returned to modern Egypt, which doesn't care about ancient Egypt and used the Rosetta stone as construction material before it was found by an officer of Napoleon)
And all the stuff we stole from India and from china and... The problem is that we never really fessed up to the crimes we committed during the empire, so it’s politically toxic to start pulling at that thread. There’s a lot we would have to apologize for that it would be far easier for our politicians not to have to talk about.
The UK should also return the entire Egyptian collection they looted.