Air Canada has been ordered to pay a French-speaking couple 21,000 Canadian dollars ($15,700; £12,900) and a letter of apology for violating their linguistic rights.
The couple complained that some signs on a domestic flight they took were only in English, while others gave the French version less prominence.
A judge ruled that the airline had breached Canada's bilingualism laws.
Air Canada reportedly told the court it would work to replace the signs.