For the first round (and the runoff), please post all results and result-related stuff in here; please post stupidities and the other stuff in the main thread. If anybody on here is interested, I'll mostly be liveblogging throughout the evening with full results as early as 18:00 (French time).
As a self-proclaimed specialist of France's electoral geography; here are my personal recommendations for some interesting and 'key' communes to watch for, which will probably be the main pastime after the exit polls. If you need a few key places to keep track of how things are going, here's where to look in priority:
Affluent right-wing strongholds: Neuilly, Paris-16eme, Saint-Cloud, Maisons-Lafitte, St. Germain-en-Laye, Saint-Ismier, Ste. Adresse, Saint-Didier-au-Mont-d'Or, Vincennes, Saint-Mande, Saint-Maur
Educated middle-class/affluent left-leaning/swing areas: Paris (entirety), Orsay, Palaiseau, Aix-en-Provence, Grenoble, Chambery, Villeneuve-d'Ascq
Comfortable middle-class suburbia (left-leaning): Cesson-Sevigne, Orvault, Vertou, Suce-sur-Erdre, Chauray, Pessac, Merignac, Tournefeuille, Blagnac, Cachan, Fresnes, L'Hay-les-Roses, Montrouge, Vanves,
Comfortable middle-class suburbia (right-leaning): Saint-Gregoire, Sautron, Le Bouscat, Bruges, L'Union, Balma, Castelnau-le-Lez, Lattes, Meylan, Fontaine-les-Dijon, Mont-Saint-Aignan, Bois-Guillaume, Marcq-en-Baroeul, Clamart, Antony, Sceaux, Levallois, Courbevoie, Sucy-en-Brie, Velizy (
), Rambouillet
Bobo central: Lyon-1er, Lyon-4eme, Paris-3eme, Paris-10eme, Les Lilas, Montreuil
Old people dying on beaches: Menton, Antibes, Cannes, Saint-Raphael, Saint-Tropez, Saint-Raphael, Saintes-Maries-de-la-Mer, La Grande-Motte, Saint-Cyprien, Saint-Jean-de-Luz, Les Sables-d'Olonne, La Baule, Dinard, Deauville, Trouville
Lepenistes4Hungarians 2007: Orange, Carpentras, Vitrolles, Marignane, Aubagne, Carnoux-en-Provence, Béziers, Sete, La-Tour-du-Pin, Aigues-Mortes, Vauvert, Saint-Gilles
Right-wing working class: Sainte-Sigolène, Mazamet, Toul, Carling, Freyming, Forbach, Stiring-Wendel, Saint-Amarin, Oyonnax, Cluses, Scionzier
Gaucho-sarkozyste working-class area: Gandrange, Tourcoing, Wattrelos, Maubeuge, Dunkerque, Montbéliard, Sochaux
Gaucho-lepeniste working-class area: Henin-Beaumont, Lens, Bethune, Bruay-la-Buissiere, Lievin, Halluin, Grande-Synthe, Roubaix, Moyeuvre-Grande, Hayange, Fameck, Woippy, Lavelanet
Socialist working-class area: Thiers, Carmaux, Decazeville, Lacq, Lormont, Cenon, Saint-Nazaire, Cherbourg-Octeville, Trelaze, Brest, Montceau-les-Mines, Digoin
Communist working-class area: Givors, Brassac-les-Mines, Commentry, Vierzon, Saint-Junien, La Grand-Combe, Port-Saint-Louis-du-Rhône, Saint-Pierre-des-Corps, Allonnes, Dives-sur-Mer, Gonfreville-L'Orcher, Saint-Etienne-du-Rouvray, Dieppe, Calais, Divion, Auchel, Carvin, Avion, Seclin, Denain, Saint-Amand-les-Eaux, Marchiennes, Longwy, Villerupt, Hussigny-Godbrange, Garchizy, Saint-Martin-d'Hères, Fontaine
'Periurbain lointain' (Distant exurban, a topic of much conversation): Mormant, Nangis, Donnemarie-Dontilly, Villeneuve-la-Guyard, Coulommiers, Lizy-sur-Ourcq, Pusignan, Meyzieu, Bourgoin-Jallieu
'Banlieue populaire': Venissieux, Vaulx-en-Velin, Givors, Herouville-Saint-Clair, Mantes-la-Jolie, Les Mureaux, Trappes, Grigny, Les Ulis, Argenteuil, Saint-Denis, Aubervilliers, La Courneuve, Garges-les-Gonesse
Favourite sons: Tulle, Neuilly, Henin-Beaumont, Massy, Borderes, Yerres, Sarran
A good bellwether might be Donzy (Nievre).