How can I become better at chess ?

the best at the start is practise and learn tactics and general principles

Marc, as for books in French, try this one (through amazon.fr for example)

okay let's see if i can shed some light i hope. first learn the basic rules of chess .start with an opening that suits your playing style . i can't say how important tactics training is , it is paramount that you learn good tactics . endgame study ,the middle game where it is chaos very hard but must be worked on  . learn how to checkmate your opponent . this web site covers all of what i have typed but if what you find doesn't suit you run a search on the web for software,books i sagest amazon.com . this is gonna take a lot of work on your part . so how much time are you willing to invest . i know you don't won't to waste your valuable time with hit and miss with books and software so read reviews before you buy saves you time and money  . find chess club in your area . this is just the tip of the iceberg . oh i forgot , loosing is part of the game and i have lost a lot so be prepared for it . when you are just staring out . Good Luck