The hotel looks beautiful but just glancing at the directions I think its possibly a bit far out to use as a base to explore Paris.
There is no metro mentioned which means its too far out to be on the line and doesnt mention RER either which means its not on an RER line.
It does mention a station nearby but Im not sure if there are trains from there directly into Central Paris - I would guess not as there is no mention of it as I assume they would say something like direct services to Paris or regular services to Paris if there was.
You are the opposite side of Paris to DLP as well so not even close to there.
There are trains from DLP to Paris which run every 5 mins and take approx 30-40 mins