Apparently WinRAR thinks it's a compressed file, which seems to be a common issue. Instead of opening it with WinRAR, right click it, select "Run As" (or the equivalent option in French) and then "Java Platform Binary"
It's on french, it says "Unable to install java"(line 1), "The followings switchs contain errors"(line 2), "Make sure the commands are valids"(last line)
Is it good ?
You can also permanently solve this issue for all jar files selecting the java VM as the default program to open these kind of files.