Hi. The Chanel store in Rome is not far from the Spanish Steps on Via del Babuino which runs from the fountain at the base of the Steps and ends at the Piazza del Popolo.
Via del Babuino, 98/101
Tel: +39 06692070
Fax: +39 066794599
I haven't been to Florence in a while. Don't think there is a Chanel there.