Paris dinner length of time

Let them know your schedule when you sit down. No big deal. They most likely will understand you’re on a schedule (not local) and help.

With the exception of specific cases (too many people, staff or organization problems or high-end restaurant) a restaurant meal rarely lasts more than 1h30, they will probably be happy that you free the table quickly in order to prepare it for thé next guests.

It's easy to tell how long this will take by observing the tables, if the majority of people seem to be waiting without getting their meal, it's an indicator that it may be longer than expected.

That being said, at 7:15 p.m. you are not likely to see many tables occupied, people come to eat mainly around 8:00 p.m.

2 hours should be plenty of time for dinner in Paris. The pace is slower in smaller towns. At worst, you skip dessert... And do let them know beforehand, just in case they have a large group or some other factor that might slow them down.