Focal make their own tweeters and some of the best. Unfortunately like Dynaudio they got out of the OEM market except for car audio.
After doing a search this morning, I'm pretty sure that tweeter has never been on the OEM market.
This is the speaker in question.
It looks as if the tweeter has a concave dome, so often favored by Focal.
The mid and tweeter are on the same faceplate.
The faceplate unscrews, and the mid looks as if comes off the faceplate.
The question is does the tweeter come off the face plate? My guess is probably not. So I suspect there is a good chance the tweeter comes with that face plate. So the repair would be transferring the mid to the new faceplate and then connecting the drivers and reinstalling the faceplate.
A picture of the back of that faceplate would be very helpful.
I have confirmed that Focal home audio drivers were removed from the OEM market in 2004. I can not find that Focal currently have a US importer from their website. I would contact them and ask if they have a US distributor who can supply you what you need. If not see if Focal will supply you from France. It is usual for European manufacturers to want proof of purchase before supplying replacement drivers unfortunately.
I think it is really misguided for speaker manufacturers not to make their drivers available OEM. From the old days, Gilbert Briggs of Wharfedale and Raymond Cooke of KEF would have told you that making their drivers available OEM and assisting home constructors was one of the most reliable and cheapest ways to gain market share. Modern business executives just have no clue.