There is an Ibis hotel around CDG which can be accessed for no charge. They rent rooms -- bathroom/shower included -- for 10-12 euros per hour. If going that route, beware that there are two Ibis hotels around CDG, so make sure you go to the right one.

Alternatively, the Sheraton CDG is connected to the airport and if you don't mind waiting in the common area there it might work. And there is only one Sheraton at CDG, so less chance for confusion.