The built-in dictionary of the Kindle will do that. It just won't tell you that je farai is the future, j'ai fait is the past and so on.
On my old e-ink Kindle, I was able to download (I think I paid for it) a French-English translation dictionary. But it meant that if I wanted to use an English dictionary later, I had to manually change it back. The system recognized it as an English dictionary and not a French one so it did not automatically use it when I read French books.
If all you want it ferai=to do then you can do that with an e-ink Kindle.