90 degrees outside and I've committed to serving French bistro fare for a small dinner party tomorrow.

Didn't notice Aigo Bouido mentioned above. That can be served cold, a la almond gazpacho.

You could also have done a Grand Aioli -- the summer Provençal feast featuring the infamous garlic mayo to dip blanched veggies, shrimp, fish, even lamb in. All is served cold.

Will be interested to see what you came up with.

When is your next party, and can we come?

Done! Menu is cheese, pate and cornichons to start, herb crusted rack of lamb, pissaladere on puff pastry, salad of watercress, shaved asparagus, lardons & poached egg with taragon vinaigrette and a blackberry clafoutis.

I am headed to the market in a few, I'll let you all know what I come up. Thank you for all your suggestions, this totally helped me out!

Awesome answers! Can I come?

After looking at your profile, I'd go for the asparagus and the tomato soup that you have posted.

Also maybe mustard greens in pesto above! I knew something was missing.

The aforementioned vichysoisses is always good for hot weather. Another standard bistro dish would be frisee au lardons. I've been thinking about this myself because I have guanciale and local eggs in my refridgerator right now. Frisee, crouton, rendered lardons, vinaigrette and runny poached egg.

I'm not sure where you're located, but spring vegetables can be great for French food - try sautéing baby artichokes and new asparagus. I also think French-style rack of lamb could work well - right now I'm imagining an arugula pesto with lots of garlic. Serve with a very light red wine, chilled. To start cold pate and cheese. But you can't go wrong with any of the suggestions! Have fun!

You should make crepes! They're not as challenging as one might think...and they can be served with a bit of vanilla ice cream, whipped cream...and a simple fruit chutney.

Chilled rose and/or Pastis before dinner. Rielletes and cornichons for the charcuterie plate. Ratatouille served at room temperature. White anchovies with artichoke spread for crostini.

Maybe for dishes you'd be eating in a bistro in the summer, you should imagine the the bistro is in Provence instead of Paris. In that case, you'd be eating Ratatouille, Soupe au Pistou, Aioli with a variety of vegetables and/or poached fish, your aforementioned pissaladiere, a platter of cheeses, tapenade...drinking a good rose...

If you need a dessert, make mini plum tarts. There was a mirabelle tree in the backyard of my host family in France and they made tarts from the fruit all summer long.
http://en.wikipedia.org/wiki/Mirabelle_plum

Obviously, it may be a little too early to look for these fresh. Maybe you can find a jam made from it, or a regular plum jam you could dab into the middle of mini tarts, accompanied by crème fraiche?

For pate, this might work for you: http://www.food52.com/recipes/9969_winter_spring_summer_fall_chicken_mousse

For Chicken Salad, Amanda's looks lovely: http://www.food52.com/recipes/4160_chicken_salad

How about a salad of new potatoes, blanched green beans, grape tomatoes, and your favorite vinaigrette. Maybe toss in some grilled asparagus.

Sounds like lots of fun, and seriously, I envy you your 90 degrees.

Pâté..both liver and tricolor veggi. (can be store brought from a good source).
Cheese plate. Fresh fruit. Bread.
Asparagus.
Lightly blanch whole green beans..tossed olive oil --heat olive oil, garlic, rosemary in a pan, remove the garlic/herbs.and toss the beans with that and top with shaved Parmesan cheese, and bread crumbs; serve at room temp.

A Vichyssoise with fresh dill garnish. A Chicken Salad with Tarragon and homemade mayo. Julia Child's Baked Cucumbers (she uses far too much salt for me tho..cut back on that-I think the original is using normal 'table salt' not kosher salt).

Sounds good!

An appetizer with crostini, radish butter and radishes and some greens? And steamed mussels?