Here's a brief digestif after having spent three months as a French student in French Africa.
First, some thoughts about the French language. Proper French is kind of like playing bagpipes. When the pipes are played well, they produce one of the most beautiful sounds heard. Yet anything less than well-played produces the cacophony of a goose giving birth. And getting to the point of playing the pipes well is really, really hard, as I've had chance to observe.
French, when spoken well, is a beautiful language. But it's really hard to speak [and understand] it well. There are a number of technical reasons for this I'm sure, perhaps purposefully conceived of by the aristocratic classes of Old that made French the exclusive language that it is.
In some sense, to speak French well you have to be in a special club, a country club if you will. Club membership entails understanding all the secret rules of grammar and pronunciation, many of which are based not on any kind of linguistic logic that I can conceive of, but on an aesthetic of what sounds nice. One must gain an intuitive discernment to know which of the consonants and vowels one is actually supposed to pronounce in any word, and equally to know which letters hang onto words for no apparent reason other than to trick novice speakers (especially English speakers, as it is, since so many French words look deceptively identical to their English counterparts).
Club membership also entails that you have the time and training [and trainer, perhaps] to learn to speak the words properly. Speaking French not only requires amazing agility of the mouth muscles, but a considerable amount of mouth muscle memory, as well. How else is one to pronounce their R's.
Having said all that, learning and speaking French in French Africa has its advantages. To begin with, most Africans speak French more slowly, rhythmically, and with "courser" pronunciations than Frenchy-French. For example, Beninese tend to roll their R's versus the French slurring. Grammatical rules and constructions are also more simply employed, if not often ignored and violated. Fewer verb tenses are used. For example, in Benin the subjunctive virtually doesn't even exist (only in the linguistic-grammatical sense, of course).
Bien sure, learning French in Benin also brings unique challenges, especially for one wanting to acquire a fairly proper comprehension of the language. As with any language that is spoke in different countries and regions, in Benin also certain French words are wielded and employed differently. "Deucement," for example, is an exclamatory word on a number of meanings: slowly (as adj.); slow down!; be careful!, I'm sorry! "Petites choses" (little things) is underwear; pate ("paste") is a staple food here made from corn flour and water. Another common difficulty, especially in more rural parts of Benin, is speaking and understanding folks who speak a French that is heavily accented by a tongue more accustomed to speaking a local languages than French.
All things considered, though, learning decent French is indeed probable and possible here. The Beninese especially tend to be patient and amiable (if not sometimes too forgiving) with an American struggling to learning French. When I've finally reached the point fluency, I may not be a card-carrying member of the high-French country club, and I might indeed speak with a tell-tale West-African accent. But I don't really see any loss in either of these prospects.