French is hard, but as a lot of common points with other latin languages, like spanish, italian, you can learn others if you know some french. Also, as you said, french got a lot of common words with english, but it also got "faux amis", words that are written exactly the same way, but with totally different meanings.
Ex : Pub means advertising in french. (Publicité)
There are a lot of other examples, but this is a good one to say you that french is a hard language, even without declinations of words like in german.