Herein, some French restaurants In Tokyo that I would advocate you visit. I've been to French restaurants in other cities (e.g., Karuizawa), but never had anything I'd recommend. Some of these reviews are not the greatest since I went to the places before I got my act together, blog-wise and photographically.
Let me start by saying this - there are a lot of crappy French places. Weeding them out is part of the art. I ain't tryin' to say I got mad skillz, but I've been to enough to know. My main objection is the places where the chef went to France 25 years ago for a working holiday and has been cooking the food he learned on that trip since then. Over time, the skills get dilluted. So I like to differentiate between 'old' and 'new' French, and I tend toward 'new', with few exceptions. But here I'll just go by price.
and you'll notice right off that I shy away from places like l'Osier. They look nice, but I know me, and I know I won't feel great paying their prices, regardless of how good it is. Your mileage may vary, and I would rather have two (or three) good nights out for the same price.
La Chasse, Roppongi Recommended only to a discriminating clientele who don't mind paying $70 for a plate of wild boar or pheasant that the chef shot himself, but still recommended. Bizarre out-of-Japan experience when you step off a deserted Roppongi back street and into a quiet farmhouse / cave in France. Wines focus on the Southwest of France, like Cahors. Big stuff.
l'Auberge de l'Ill, Roppongi I still can't believe I paid $50 for lunch in a huge room that felt just like I was in a French chateau. Then again, it was worth it, or rather it would have been if I had actually paid. I'd love to work up the courage to go for dinner, but...not enough to get there (from about $150, I think; see comments above).
Yonemura, Ginza Definitely a forget-the-price destination, but if you can forget the price, I'm pretty sure there will be some things in the French-Japanese fusion here that will astound, titillate and delight you.
Reims Yanagidate, Omotesando Pretty high-end by my standards (starting at Y8500, I think), and popular with ladies of a certain socioeconomic standing, and a little bit old fashioned, but there's nothing wrong with glasses of rose champagne and crab salads, is there? Very proper.
Not so expensive
These are still in decreasing price order; expect courses around Y6500~ at the first couple.
Merveille, Nihonbashi I decided a long time ago that when people asked me that silly question "What's your favorite restaurant?" I'd just tell them it was Merveille. It almost certainly wins my award for most-visited restaurant-in-Tokyo, which is high praise when almost no place gets past 1 visit. It's not the greatest restaurant in Tokyo, but it's certainly very good, with food, atmosphere, service and cost performance that are exactly how I like. So maybe it really is my favorite restaurant.
Ohara et CIE, Roppongi Strange that I've only been here once for lunch and it made such an impression on me, but it did. I'd love to go back for dinner, and recently noticed when passing that it's less expensive than I thought. Just perfect cooking with only a proper level of fuss.
Salut, Ebisu Cheerful yet elegant (I think it's the mix of lemon yellow and fieldstone wall treatments), plus interesting choices and quality cooking, all for a good set fee. The kind of place where I really struggle to choose just one course from each section.
Bistro Lugdunum, Kagurazaka Calling it a bistro is modest, false or genuine. It's bistro food notched up once or twice to be refined (and smaller) (and pricier - Y5k, 3 plates - but still cheap for Tokyo). I think this is the best in the neighborhood in this price range, and that makes it one of the best in the city.
Provinage, Roppongi Must like it - I've probably been here at least four times in various configurations of people. It hits the same blend of atmosphere, food and service as Merveille, but down one or two notches (and with a corresponding price reduction).
Viron, Marunouchi For bistros, many are cold but few are frozen (that's a margarita joke). Viron is the chosen one as far as I'm concerned; the decor out-Frenches the French (who probably find it a bit cartoon-y), but all your bistro favorites are always on the menu, and the cooking is great. One point of note is that it's not as cheerful-cheap as you'd want from a neighborhood bistro, but then again you do get all you can eat of their fantastic baguettes.
Les Enfants Terrible, Azabu Juban If you're not going to Viron, or if you want something a little quieter, a little classier, a little more expensive (oops), and a little more in Azabu, then LET is it. I like the almost-gothic atmosphere, and the chance to sit by the big windows if they're open.
Le Pre Verre, Omotesando Renovation in 2010 took out the floor-to-ceiling windows with a view over the city toward Shibuya, but the food remains lovely in a modern-bistro way, and the pricing is still very, very sharp considering the quality. Also all bio-wine, if you're into that sort of thing.
Brasserie Bec, Yoyogi Uehara Probably the most old-fashioned place that I could envision recommending, but the cooking is pretty timeless in all its rib-sticking glory. Any deficiencies are quickly papered over by the bargain pricing scheme.
Brasserie Gus, Kagurazaka Oopsie, this is old-fashioned too, but high quality and blisteringly cheap. Your wallet and gullet will both be startled. Positively.
As long as I hit that Kagurazaka topic, I've gotta tell you that I went on a big tear in November 2010 and went to a ton of Frenchies in Kagurazaka. The best ones are above, but you could look here