RIYADH/PARIS, Oct 13 (Reuters) - Saudi Arabia has lifted a 15-year-old ban on French beef, opening one of the markets closed to France due to past cases of mad cow disease and offering potential support to a French meat industry hurt by low prices and a Russian embargo.

The re-opening of the Saudi market was announced during a visit on Tuesday by Prime Minister Manuel Valls, and comes as French officials have made exports a focus in tackling a downturn in the meat sector that led to angry protests by farmers this year.

France is the EU's largest agricultural economy and also its biggest cattle producer, but currently exports beef almost entirely within the 28-country European Union.

France experienced cases of bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, in its herd from the 1980s during a European outbreak that began in Britain.

Earlier this year, it obtained "negligible risk" status for BSE from the World Organisation for Animal Health (OIE), indicating the last infected native animal was born more than 11 years ago, and has since secured the opening of beef trade with Singapore, Vietnam and South Africa. ID:nL5N0YI3AJ ls of less than 30 months, following approval in principle it gave a year ago for EU beef. France aims to obtain access for meat from older animals after further talks, the farm ministry said.

France completed a certification process last week in time for Valls' visit and French beef was served to participants at a business event attended by the Prime Minister in Riyadh.

Saudi Arabia took 160,000 tonnes of foreign beef and veal last year, the U.S. Department of Agriculture estimates, making it one of the world's largest importers of the meat.

Saudi beef imports are worth about $500 million a year, according to French farm ministry. SVA Jean Roze, one of more than 30 French firms now certified to export beef to Saudi Arabia, hopes to export 3,000 tonnes a year there, Marc Feunteun, the company's export manager, told Reuters.

However, France will face competition in the Saudi market from big exporters such as India and Australia, and is still in discussions to gain access to China and the United States, the world's two biggest beef import markets.

(Reporting by Elizabeth Pineau in Riyadh and Gus Trompiz in Paris, editing by David Evans) ((gus.trompiz@thomsonreuters.com; +33 1 49 49 52 18; Reuters Messaging: gus.trompiz.thomsonreuters.com@reuters.net))