Charles Duguay was charged with speeding on the Champlain Bridge in early 2008. (Canadian Press)

A Quebec man fined $718 for speeding on the Champlain Bridge says he shouldn't have to pay the penalty because there are two sets of traffic laws on the province's books.

Sherbrooke resident Charles Duguay was slapped with a ticket in early 2008 — and 10 demerit points — after police caught him driving 122 kilometres per hour over Montreal's Champlain Bridge in an 70 km/h zone.

The initial fine, worth $530, was issued under Quebec's recently amended traffic laws, enacted in April 2008.

But Quebec's old traffic fine structure is still in effect, because the amended law did not rescind previous rules. Under the older law, Duguay's infraction would have cost him $250 and five demerit points.

Duguay's lawyer Claude Villeneuve argued that he is entitled to pay the lesser fine if both are still technically in effect.

On Tuesday, Quebec court Judge Claude Provost rejected that argument, ruling the two fine structures are complementary.

Duguay said his fight isn't over, because he plans to appeal the ruling in Superior Court.

More than 20,000 Quebecers have been fined for traffic violations under the province's tougher laws.

Quebec Transport Minister Julie Boulet said her ministry will review the amended law to correct the situation.