We do not know yet the identities of the terrorists, so only a guess based on the previous three years of attacks in France.

also the TVs are mentioning terrorists speaking French, which if confirmed strongly support this guess.

What he means is french muslims , which are nationals/residents. Charlie Hebdo attackers were french nationals, though having a north african/african background.

Almost certainly. But it does make a difference. Most French muslims come from Algeria and Marrocco and can't really claim to have been affected by the war in Syria. There are deeper roots to home grown terrorism than the Syrian conflict.

At least they speaks french according to witnesses http://www.mediapart.fr/journal/france/131115/paris-frappe-p...

There were eyewitness reports that the gunmen were talking to each other in French. So, that's something. If they were recently-arrived refugees that probably wouldn't be the case, though it doesn't rule out long-term embedded groups.