Since I stayed at Hotel Route Inn at the same street in Sapporo, I had to try it out when I found out about it.
I loved the rice in the menu. Had some poppy seeds on it. The menu was Tonkatsu containig tofu, probably potatoes and carrots nicely seasoned. Some side dishes with vegetables, Miso soup and rice. It was nicely arranged.
The owner speaks English and French. She was very helpful, since I didn't understand all the Menu-Kanjis. Definitely, I will go to this place again.
I was told, that the restaurant is open only for lunch time at the moment.
look out for Hotel Route Inn when you go down the stairs at the north exit of Sapporo station. Cross the street and go left. Watch out for an orange sign showing au. This is the store right after the Shindo Fuji. The Restaurant has a blue sign, it is downstairs. The Address ist 4 Chome-3 Kita 7 Jōnishi, Building 3F.
Take a look at the picture at Google street view
Cons: hard to find