It's Demography, not Politics, but still...
Out of Canada's 308 "ridings" (constituencies), 40 are over 10% French speaking and over 10% English speaking. They form something of a belt from Nova Scotia to Manitoba via Montréal and Ottawa cities.
(Note that the census asks for "mother tongue", prompting many immigrants and children of immigrants to mention the language from back home, even if they speak English these days. This seriously affects the number of over-10%-English speaking seats in Montréal.)
Actually it *is* politics... the area used to be called the Red Belt (Red as in Liberal).
Let's see if it still is...
West Nova: Acadian, Liberal
Egmont: Acadian, Liberal
Acadie-Bathurst: Acadian, NDP (Yvon Godin's seat. It's an old Zinc mining area)
Madawaska-Restigouche: Acadian, Liberal (NDP came second though)
Beauséjour: Acadian, Liberal
Miramichi: Acadian, Liberal
Moncton-Riverview-Dieppe: Acadian, Liberal
Tobique-Mactaquac: Acadian, Liberal, Bible Belt
Gaspésie - Iles-de-la-Madeleine: BQ. I think some Acadians.
Compton - Stanstead: BQ, Eastern Townships I think...
Brôme - Missiqoui: Liberal, Eastern Townships (Loyalists) again I think...
Outremont, Mount Royal, Notre-Dame-de-la-Grace - Lachine, Westmount - Ville-Marie, La Salle - Emard, Jeanne - Le Ber, St-Laurent - Cartierville, Pierrefonds - Dollard, Lac-St-Louis Brossard -La Praire: All Liberal (though I think that one is going to a recount)
Châtauguay - Saint-Constant: BQ
Saint Lambert: Can't remember.
Laval - Les Isles: Lib
Vaudreuil - Solanges where the Ottawa and St Lawrence rivers meet: Jack Layton grew up here, suprise BQ gain
Hull - Aylmer and Pontiac: Both Liberal
Ottawa Centre, Ottawa South, Ottawa Vanier, Ottawa Orléans - ie all Ottawa City ridings safe one: All Liberal except for Ottawa Centre (Ed Broadbent's seat)
Glengarry - Prescott - Russell and
Stormont - Dundas - South Glengarry to the South of Ottawa, to the east of Vaudreuil - Solanges. Glengarry etc is majority French speaking: G-P-R is Liberal (Don Boudria's seat) and saw some nasty language politics (Anglo's: Tory, Franco's: Ultra-Grit), S-D-SG is Tory (same language wars apply)
Timmins - James Bay: Franco's went there 'cos of mining. NDP seat.
Nipissing - Timiskaning: Liberal. Used to be Mike "Godfather" Harris's seat provincially (strange as this may seem).
Nickel Belt: Liberal (provincially NDP though) Franco's vote Liberal out of reflex.
Algoma - Manitoulin - Kapuskasing: Liberal (Used to be L.B.Pearson's seat. NDP did shockingly well though)
Provencher: Metis vote Liberal, everyone else votes Tory. Very safe CPC seat.
St Boniface: Liberal (NDP provincially though).
The Red Belt still sort of applies...