Pouyanne said the launch of the plant, expected in early September, was on schedule despite a call by a farm union to block oil refineries in France over a decision to allow Total to use imported palm oil as a feedstock at La Mede.

FNSEA, France's largest farmers' union, on Thursday called for the nationwide blockade from June 10.

Total has said feedstock for the 500,000 tonnes per year refinery will be made up of around 60 to 70 percent vegetable oil, and around 30 to 40 percent from animal fat, used cooking oil and residue from used palm oil.

The 60 to 70 percent of vegetable oil will include palm oil, rapeseed oil, sunflower oil and soy oil.

Pouyanne told journalists on the sidelines of a Total shareholder meeting in Paris that the company had identified around 100,000 tonnes of animal fat to be used in place of palm oil, cutting palm oil usage to below 300,000 tonnes.

"I think we have a solid business case for the biorefinery," Pouyanne said, adding Total would continue talks with farmers and had decided to buy 50,000 tonnes of French rapeseed per year for the plant.

"Sincerely, the 50,000 tonnes is not most profitable in the feedstock that will go into the refinery," he said.

France consumes around 3 million tonnes of biodiesel per year and produces about 50 percent of that in France, importing the rest including 750,000 tonnes from southeast Asia and Argentina.

"Our project represents around 500,000 tonnes ... the La Mede refinery project will make France a lot more independent," Pouyanne said.

(Reporting by Bate Felix; Editing by David Holmes)