We did a 2 week trip in Italy. If Other countries are doing what Italy is on trains, I felt safe. 50% of seats marked to keep open. On trains with reservations 50% of sears blocked. Doors are marked entrance and exit to keep traffic moving through train in one direction. Train bathrooms were spotless. Hand sanitizer in every vestibule. Masks required (and worn at stations and on trains). At train stations they have arrows directing foot traffic. Round stickers to mark where to stand to prevent congregating.
At Milan Centrale, they actually roped off the station and there was one way, counterclockwise direction for all foot traffic from one end to the other in the central hall. To enter the track area, they took temperature of everyone. Not all cafes and restaurants were open.
We frequented mostly outdoor restaurants and cafes. Tables socially distanced and spread out. All wait staff wore masks. Any indoor business required masks. Some shops took temperatures, some provided gloves if you wished to touch anything as you shopped. We also found lodging that had outdoor balcony or terrace so we could enjoy being outside mask free. Hotels gave implemented Covid cleaning protocol, everyone where’s masks and hand sanitizer always available.
I also followed the Covid 19 site for Italy that reports how many new cases per day in the Provinces we visited. With very few new cases reported daily at our destinations, we felt the risk was low to travel there. Italy’s positive cases are less than 1% of the daily tests conducted (50-70,000). So find the stats for Paris to assess risk.