This type of viola is very common in Montreal.
It flowers in early spring, and it grows everywhere, especially in shade and spreads like mad.
Could it be viola canadensis?
Thanks a lot.
It looks like Viola sororia var. priceana, also known as Confederate Violet.
Looks like a form of Viola sororia that is sometimes called confederate violet
Thanks Carol and Lycopus, I believe you're right :)