I'm not with Laminar Research, just a fellow simmer in the UK, but presumably the 'LFPG' means Paris Charles de Gaulle?
If so, I have taken a flight in and around LFPG and I'm current getting 33-45fps depending on local scenery. I do not have any special addon scenery for the Paris region.
My PC spec is i7 8700K 3.70 GHz CPU, Geforce 1070 8MB GPU, 64GB RAM running two HD monitors concurrently.
1. Does this problem only occur at LFPG?
2. Do you have any special scenery packs for the Paris area?
3. What monitor resolution are you running?
4. How have you configured your X-Plane 11 graphics settings?