This "underground" French restaurant has been going for about ten years and it's easy to see why. The food and service are superb and this is a great place for a business lunch. Watch out though as the price of the set menu is deceptive. We were offered an amazing cheese plate but it added a few thousand yen to the bill! Still worth trying especially where you need to impress without being overly pretentious. They also have a theme night featuring a different style of wine each month.
Update: I have now tried Le Petit Bedon for dinner. My dining partner and I took the 12,000 yen tasting menu and wow! The dinner comprised of an amuse gueule of a baby tomato in jelly, a "pyramid" of scallop with wasabi ice cream, sauted foie gras with herbs and baked apple, a scampi and pistou pie with crustacean sauce, sea bream with a light yuzu sauce, slow cooked beef cheek, cheeses and a fondant chocolat to finish. Everything was amazing, and I was so full by the end of the meal my tummy hurt! I walked all the way home to my place near Hiroo to ease the guilt. I highly recommend this place. The service is formal but not stuck up, the food is excellent and the prices are at least about 30% lower than what you would expect to pay at one of the better known and fancier establishments in Tokyo.