You'd have to balance that with the likelihood of irregular ops. FR have a very good record in that respect.
I would not necessarily avoid flying FR just because of that. I do my utmost to avoid FR, but for other reasons: I feel very uncomfortable about buying a ticket from an outfit which so openly and cynically rejects anything remotely resembling ethical standards, let alone concern for their customers. But to each their own.
An alternative, if somewhat less convenient, is to take a train down to NAP (about 2 hours from Rome) and fly to ORY with Easyjet. It involves obviously extra time on the train but, OTOH, you fly to ORY rather than BVA and probably save a good hour in the airport to city transit at the Paris end, and the NAP-ORY flight leaves in the afternoon (15.20 mon-sats and 15.45 suns). Meridiana also offers cheap o/w fare from NAP to CDG, with a midday departure.

The easiest would, of course, be to fly AZ or AF, buying a return and throwing the return away. Yet another option would be to fly Meridiana (or AZ) from FCO to LIN and then LIN to ORY on Easyjet but you would have to plan a substantial layover in case of delays on the FCO-LIN flight.