The trend is probably still for English sounding names for brands and web sites but that might depend on what “[french word]” is too.

You might also use xxx-en-ligne.fr.

May be I am wrong but making a quick googling I got the impression that the trend are web adresses of the form that @jlliagre suggests. For instance

http://www.academie-en-ligne.fr

I did also find some sites without the hyphen (tiret).

Here are is a relative Ngram.