Legally, the government has to reply within 18 months after your application, according to the page about Naturalisation on service-public.fr, an official website (idk if I may post links)

In some cities like Lyon, you can indeed wait 1+ year for the process.

Informally, the Administration / "Préfectures" are infamous for being slow, and requests are processed in each administrative division, so you'd rather not be in a city where there are a lot of applicants.

I mean, anyway, being naturalised here happens when you are in a stable situation, and is very symbolic in that case, so there is no rush.

If you live in France, you are welcome to be in here, you can vote for local elections if you're from the EU, you pay taxes or not according to your income, like anyone else, you can access the full social security system and other public services,...

I understand that being French is a stateless concept about living in here and sharing the moment, and it's not just a legal status ; so it makes sense if it takes time, but it arrives eventually.

Depends how good or useless your existing passport is. Travelling as a French national is a lot easier than travelling as an Algerian or Lebanese national. If you’re a Canadian or USian, it’s largely meh to get your French citizenship to travel.

It might be different now. I had read up to 2 years. There is a language requirement, but there used to be no test requirement, so the interview was to at least evaluate that.

Now that they require test results, there’s an added cost, but one less thing to evaluate directly in the citizenship process, so maybe they’ll do away with the interview entirely.