I read that :

Système :
Windows 8 / 10 (64 bit)

So, it cannot run on my windows 7 ? :/
You know that seven is still used, more than windows 8 ?

It only says the game is no supported for 7, which is no longer supported too by Microsoft.
So devs no longer support 7 so they don't have to correct viruses of 7.
But the game may still work good with 7, ask this at 7 users.