In brief: Le Regent is a clean, nice, cozy, very small, nothing fancy hotel but with a perfect location. If you're not a person that stays in your hotel room this is a great place to stay if you want to go out and see Paris.
You really live in the city, close to the Louvre, Luxembourg Gardens, Notre Dame Cathedral and more, and it's a quiet hotel. In this area you'll have many restaurants and food places as good as anywhere in Paris. We tried a lot of food places and it doesn't matter where you eat, the food is on average 3 out of 5 and with a soda/beer/tea/coffee the cost range from 18 euros to 30 euros per person. We didn't eat breakfast at the hotel so I can't speak for that.
Our room, a double bed room, was very small. And I guess you should expect that from the other rooms too. We hade difficulty unpacking and kept our clothes in our traveling bags. Yes there were hangers but no where else to put our clothes. The beds were comfortable and the room was dark at night and had a great working AC. You really want an AC in the summer. It gets really hot and humid.
The staff was okey. Some were really nice and helpful but one guy was so crappy that he dragged them all down with him. I started wondering how the hell he got that job. He was definitely not cut out for social contact.