The Paris-Frankfurt route is operated by Hop ! separately from terminal 2G, a satellite terminal. You will do all your check-in/boarding there, it is a small separate terminal with not too many people as it is only Hop ! flights.

Originating from Paris and arriving by car, you can tell the taxi/get dropped off directly at 2G. I would arrive 1h before depature.
If you are arriving via public transports (RER, TGV), it's more annoying as you have to take a shuttle bus from 2F to 2G, which itself is a 10-15mn bus ride. So if I were arriving via transports, I would plan 1h30 to allow for the shuttle to 2G.

Honestly, taking the TGV from Paris-Est to Frankfurt is the better solution. When I do my trips between the two cities, it is by train, and statistically more people take the train than the plane between the two cities.