while both the Sistine Chapel and the city of Paris are 'must sees' I
feel that given the time available you will exhaust yourself.

However I am happy to offer suggestions,

Don't drive I enjoy exploring as well but it will be too tiring.

TGV goes Geneva Paris in 3 hours I would anticipate 8 by car and car
is irrelevant in paris anyway.

Fly paris - florence.

can you fly out of rome?

BEST regards

O'donnell