Bonjour Arenda,

I had a look again at this error and I can see that I missed it when I first replied to you. We are amending this error now. 

Merci et bonne journée !

Bonjour Arenda,

Thank you for query. You are correct that 'rez-de-chaussée' does have two hyphens. I have just looked at the fill-in-the-gap exercise you mentioned and I cannot see the error you've seen. 

Attention:

the basement = le sous-sol  -  the ground floor = le rez-de-chaussée

I hope this is helpful.

Bonne journée !