I haven't seen the film yet, so I hope I'm not mistaken regarding the meaning of "Mass"*, but I don't think many people in France know that Mass = Massachusetts (I did copy/paste that word ). And not many people know that Boston is in Massachusetts, Boston is a famous city of course but I think there's just a general knowledge that it's on the East Coast above New York.
The book wasn't published in France until the film came about, so no rule about "sticking to the book's title" here.
Looking at the title, in French people see "Black Mass", they'll think "Masse noire", as in the weight of something black.
Well, in most French posters for Black Mass, you see they wanted to convey the fact that it's a gritty drama, not a documentary about dark matter : besides the word "criminal" in the title, you have the word gangster, and Johnny holding a gun (like this one), differing from the most famous posters with only his face on the poster and the rest of the cast in a red banner (this or that) - but they're not going that way with the steelbook edition obviously.
* I imagine Black "Mass" is a play-on-words, refering to the State where the film takes place, but also the religious ceremony (a "mass" in English is a "messe" in French). I guess if they translated to "Messe noire", you'd get a pretty good title imo, without refering to Massachusetts. But they went in a different direction, which I don't approve of either. "Messe noire" is okay, keeping "Black Mass" would have been better, but then again, they would have lost people doing that imo.
Why some studios decide to translate original titles into other English titles? Marketing geniuses I guess. Judd Apatow mentioned that reason why he talked about the French title of Trainwreck (= "Crazy Amy") during French interviews - the German title is "Dating Queen" btw, we're not alone . They want to lead French people to believe they speak better English than they actually do, by using simple English words to convey it's a foreign film but no words that are too hard to understand or prononce (e.g: "hateful eight" could be seen as tricky) — "Strictly Criminal" literally means "Strictement criminel", everyone understands, and "Strictement criminel" isn't a very good title, "Strictly" is shorter and 'cooler' I suppose .
I imagine Black "Mass" is a play-on-words, refering to the State where the film takes place, but also the religious ceremony (a "mass" in English is a "messe" in French). I guess if they translated to "Messe noire", you'd get a pretty good title imo, without refering to Massachusetts. But they went in a different direction, which I don't approve of either. "Messe noire" is okay, keeping "Black Mass" would have been better, but then again, they would have lost people doing that imo.
@Bunk As coincidence would have it, I was browsing Amazon's Canadian site earlier today and saw that for its Canadian dual language titled release, Warner had actually gone with the French title, "Messe noire".
I've noticed before that film titles in France often differ from their French Canadian counterparts. I assume that the French language has evolved differently in the two countries, in much the same way that the English language has evolved in the various countries where it is spoken.
Interestingly, given our earlier discussion about the French release of "The Hateful Eight", I see that in Quebec that film was given the title of "Les 8 enrages" (The Rabid Eight), again quite different to that used in France, "Les 8 Salopards" (The 8 Bastards).
I'm not surprised they used "Messe noire" in Québec. Often times I've noticed that when they translate film titles, they're very literal, word-for-word translations. For The Hateful Eight, they made the choice to go with "enragés", and here's my theory why: one big thing where there are differences between Canadian French and Metropolitan French are the insults, and as it turns out "salopard" is an insult in France but maybe it isn't in Québec. For instance, I'm looking at this page and they're listing a few insults: "Christ de plote sale!" is extremely offensive in Québec apparently, it translates to English as "Fuc*in' dirty c*nt!", but I had no idea what it meant until now ("sale" is dirty, but the rest... I had no idea — that "christ" word in very present in Québec it seems, maybe a religious influence, much like in American films/shows I see people saying "Jesus" or "Jesus Christ!" (see here )).
Anyway they often translate titles because in my view, being a French-speaking province, and a big one (25% of the Canadian population, it's big but still a minority), in an otherwise English-speaking country, they want to protect their official language, whereas in France you'll find many translated titles, sure, but also studios are increasingly keeping original English titles.
Québec is protective of their language whereas in France we don't have a majority of the population speaking another official language, so we drop the ball and include English words everywhere — not just film titles, that I'm okay with, but in general conversations: I just saw on twitter someone saying "je l'ai unfollowé" (= I unfollowed him/her)... that's someone conjugating an English verb in a French manner, even though there are perfectly acceptable words for saying that in French (e.g: "j'ai arrêté de le suivre ("I stopped following him"), "Je ne le suis plus" (I'm not following him anymore) - "suis" is tricky for foreigners I assume, because it means both "am" (I am / je suis, in to be/"être" verb) and "follow" (I follow / je suis, in "to follow"/"suivre" verb)).
For example, I'm looking up titles of films based on steelbooks threads from this section, and the title of Last Action Hero in France is "Last Action Hero", while it is "Le dernier des héros" (= literally, "The Last of the Heroes") in Québec. "Mad Max : Fury Road" in France is "Mad Max : La route du chaos" in Quebéc (to me that's the best translation possible for "Fury Road", because "La route de la fureur" would be a bit odd) .