I don't remember seeing ads about Ramadan in the Paris metro before this year. Clearly a bigger part of the population than ever is observing Ramadan, the yearly month-long Muslim fasting time, which ends this year on July 28th.
This ad is for a telephone company, Buzzmobile. It says, "Unlimited calls 24h/24. I can gassar without counting!" A footnote says that gassar means "talk or gab."
An alarmed-sounding article in the Nouvel Observateur points out that the French have tended to be leery of any kind of marketing directed at one ethnic group in the population; the French government is not even allowed to ask ethnic questions on its census, so no one really knows what percentage of the French are from different ethnic groups.
The woman in the photo is wearing makeup and a full "correct" veil, the kind she wouldn't be allowed to wear to a public school in France. The ad people look as if they did their job a bit hastily, says the French Muslim consumer site Al-Kanz, detailing the problems: the word gassar is specific to Algerian Arabic; in Morocco and Tunisia it's pronounced differently. Also, French North Africans often don't even speak Arabic any more, and many others prefer to speak Berber with their families, not Arabic. Moreover, the period of Ramadan is supposed to be a serious one of improving your character by moderation in all things, so chattering endlessly on the phone is not exactly celebrating it. And isn't showing a young woman who only wants to gab a bit sexist?
Anyway, the ad is creating buzz, and as the saying goes, there's no such thing as bad publicity.