The month of November is, on average, the cheapest month to fly to Nantes from Canada, with most prices found around 866 C$. If you aren’t able to travel during the month of November, then book flights to Nantes from Canada during September instead. Flights to Nantes in September, while not as cheap as those in November, still average around 878 C$.
The cheapest day to depart from Canada to Nantes is on a Wednesday when prices can be found for as low as 916 C$. Flights from Canada to Nantes on a Sunday will generally be more expensive and average around 1,201 C$. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.