Is the pronouncer we listen to computer generated? I sometimes have trouble understanding the french being spoken by the computer. It might be better if they were recorded by a real person, who may distinguish between similar - sounding words more easily for the listener's ear.
The French pronunciation generated by the computer is pretty accurate with certain very small exceptions. Your big problem is that certain sounds, represented in French by the letters "u" and "eu," for example, do not occur in English at all and require a formal description and some practice before adults can pronounce it easily. There are other similar problems, in French, which I won't go into now.
What this means is that if you are older than your teenage years, you really cannot learn to pronounce French accurately by simply hearing it without a formal introduction to its phonology (pronunciation system). This is also true in the case of German and Portuguese. It is even true of Italian and Spanish, though to a considerably lesser extent.
Duolingo should be considered only one of various possible tools you can use to study the languages it offers, including books, classes, recorded courses, and other similar materials.
(Also, it is important to note that Duolingo's electronic pronunciation generator does have some glitches--especially involving the truncation of words--which hopefully will be largely taken care of with further refinement.)