I spend a lot of time in France, not to far from the Swiss border (Morzine).
The white stuff on the floor could be just chalk.
The water there was always opaque, mountain water has a lot of chalk.

Be careful with Lino, in the past they often used asbestos for the base.
Do not try to remove it before you have it checked.

Dealing with French contractors can be a challenge, they are not as punctual as the Swiss.


Rob