That's a neighbourhood I am very familiar with and my experience has been quite different.
Every body I have come across spoke conversationally fluent. Street French, including the guys at the, Peking duck shop. I usually visit when I am in town. Maybe not the stick up bum, academic/formal, French that the bourgeois speak, but, perfectly good, everyday, man on the street, French.
That goes for my many Vietnamese friends in Paris and in Brussels, totally fluent in the local lingua franca, including Flemish /Dutch, English and German in my top mate, Phuc's, case.
My biggest surprise was when picking up a much larger car to drive to Nice in, from the enterprise car hire booth at cdg airport last stay. Meeting an Australian, from St Kilda, hand over the car, who spoke better French than you type English, and he'd only started living there 2 years ago, married to a French citizen.
It's not the same thing, in my opinion, as majority of non native French citizens do speak the local language, just fine.
I include 8 members of my own family that are Italian nationals, who have lived in France for over 3 decades, one even worked quite high up for the, French ministry for defence, providing the armed security detail that protected arms shipments internationally.
The opportunities are the same for everyone, providing you have a good work ethic, a willingness to not rock the boat, minding your own business and willingness to succeed, in a liberal, Western, country.
I would say that Italy and Greece would be much tougher for newly arrived immigrants to fit in, culturally, certainly harder in regard to patience and tolerance. Just read the racist graffiti sprayed on walls these days, and the heated arguments on the news between the people and government officials on the nightly news toward immigrants from African nations. Pretty angry stuff...