Double Insurance When Renting??

We are soon to be renting a house whilst our is being built. Everything is very amicable with our new landlords, they don't speak English but their daughter is fluent.

We asked her yesterday about insurance for the rental property assuming we would be responsible and following is her answer.

2) The law says that a house for rent has to be insured twice i.e. by the owner and by the tenant. So you have to insure the house on your own; the insurance contract must start from the day you take possession of the house. This insurance is compulsory and cannot be part of the rental bill. It is called an "assurance locative."

I've been all over the Anglo info "renting" area and whilst it talks about us insuring it it doesn't mention "double insurance" can anyone throw any light on this please.