Back in the late 1970s friend and I decided to hitchhike through Europe - we were living in London. We got zero rides from Calais and ended up catching a train to Paris, arriving at nearly midnight. The hotels near the station were too expensive, and we were sitting in the gutter looking at a map when a young man asked if he could help.
He said he knew where there were cheaper hotels, and offered to walk us there. He was charming, funny and warm, and we had a great conversation as we walked. After a mile or so he said, well this is crazy, why don't you come and stay at my place? My mother won't mind.
He took us to a grand Paris apartment, like from a film. His mother was already in bed, but she called out instructions for putting fresh sheets on the sofas. Hearing that we hadn't eaten all day, he took us out for a meal at a couscous restaurant nearby (it was after 1am by now). He explained that he had to leave early in the morning because he taught at a school for special needs children outside the city, but that his mother would give us breakfast.
And that is what happened - she was charming and warm, and acted as if it was perfectly normal to feed two random foreigners her son had brought home in the middle of the night.
I've loved Paris ever since.