Let's talk about food!
Le florimond in Paris... amazing service and reasonable price. The matrie D is something else and definitely makes the experience memorable. Talk about orchestrating a dinner. We chose the menu prixe fixe and it was like art how they picked wine for the different courses. They served us like 4 different types of foie gras and smelly cheeses. I think I honestly was drunk after that but rememeber being very happy and having 3 desserts with espresso. Amazing experience. There were tourists in there but it wasn't a tourist place and plenty of Pariseans as well. Make a reservation!!
Lavante Comptoir was a wine bar I fascinated about for a long time... finally went and loved it. Standing room and finger food with great wine. Great atmosphere.
Also, it's May. Get two bottles of ros, some olives, some cheese, some cured meats, and a baguette and go sit in a park or the edge of the river and get drunk. Then make out with your wife/girlfriend.
In London I had several good meals.
Vasco and Piero's Italian in SoHo. Family run business.. the son is the front of the house. I was feeling indecisive that night and I asked the waiter (who happened to be the head of the front of the house) what the chef would like to cook. He brought me a steak, but since I had asked about the lamb, they chef also brought out some lamb. He hand delivered it. It was the old man. The old man was still back there cooking. He said lamb cooked on a flat top was so simple, but was his favorite meal and he wanted me to try it. He didn't even know me but he loved sharing food that much. Made my night. We drank great wine here and then shut down a bar down the street.
I also made my family try some good ramen at Kanada-Ya. Ippudo is across the street and this is more of a hole in the wall place. There was about 15 people standing in line outside so we waited it out and it was definitely worth it. The onigiri was amazing and the ramen was as well.
I love both of these cities and have been to both twice, once with family and once on my own. A lot of suggestions seem to be aimed towards older/family, but on the off chance you're under 40 and may be looking for edgier opinions or things to do at night; let me know.
Both cities have class but both cities have a fair amount of charming grunge. If you're high class here, of course enjoy that, but I always think it's worth getting out of your comfort zone and doing something different. On the contrary, if you're young and a little rough around the egdes, class it up a bit and drink some fine wine and have afternoon tea on a high terrace somewhere like royalty.
Regardless, have fun and enjoy yourself!!