Paris is an expensive place to visit and Gerard's place is an excellent value for money. Yes it is in a working class area of Paris and the first impression of the neighbourhood is not great, but if you are coming from a big city then it's just normal life. You may be approached by beggars but just ignore them. I walked in this area quite late in the night but did not feel unsafe at all. Just take normal precautions.
The metro stop is almost opposite the building, which will take you to central Paris in no time. The bus/tram stop is also pretty close. Plenty of cheap eateries nearby, a macdonald 10 minutes walk away and a supermarket next door.
Gerard is a very nice host. He was a bit unwell when I was there but still took the trouble to get up early in the morning to make me a cup of coffee and offer cake and yogurt. He speaks reasonable English. There is coffee making facility in the room also. Bed was nice. The room overlooks the busy road but the noise was not too bad. I was very tired and slept well.
Toilet and shower small but clean and adequate.
The only note of caution for future travelers ( no fault of Gerard) : the bus 350 route from CDG airport has been cancelled from 30th April. I waited for 45 minutes before realising that. Catch the train to Gare du Nord and then to Porte de la Chapelle. Couple of changes but fairly easy.
Highly recommended.