The cheapest flights to Canada are available are on routing from Brussels to Montreal. There is also competitive offer from Air Canada and their partners, you may find both booking samples below. Montreal is second largest city in Canada and capital of Quebec province. (and is one of the five largest French-speaking cities in the world). In case of interest do not delay with your booking as very limited travel options are available.
Please see also our short update below as you may also consider to book an open-jaw flights on route Brussels to Montreal and from Toronto to London for similar fare. In case of interest please look for limited travel options between April and June 2015.
Booking samples
NL - Brussels - Montreal for €367 (+€22 booking fee)
NL - Brussels - Montreal for €367 (+€22 booking fee, based on Air Canada)
DE - Brussels - Montreal for €365
EN - Dublin - Toronto for €388
EN - London - Toronto for £316
EN - Glasgow - Toronto for £316
EN - Manchester - Toronto for £319
Brussels - Montreal and Toronto - London for £275
Plenty of low-cost airlines are connecting these airports with other European airports. We recommend to use service of Skyscanner to quickly find out which low-cost airline offers the most competitive fare.
Booking sample of cheap open jaw flight to Canada for €365 here. In this case you would be departing from Brussels to Montreal on 6th of May and returning back from North America to Belgium on 19th of May 2015.