Hollande opened the 18th Vinexpo in the historic French port, which has been the centre of France's wine exports for centuries, at 10.00am on Sunday.
He repeated his opposition to an amendment to the 1989 Evin law passed by a parliamentary committee during the week, while accepting that there could be "clarification" on certain points.
The changes would end attempts to prevent drinks firms' names appearing on television and cinema through measures such as a ban on them sponsoring sporting and cultural events.
Critics claim that some media outlets have been fined for naming alcoholic drinks because of the law.
But, in an interview with regional paper Sud-Ouest, Hollande pledged to promote wine and spirits sector, fight for its interests in the trans-Atlantic trade deal currently being negotiated with the US and help the export of wines and spirits, which earned the country 7.6 billion euros in 2013.
The foreign affairs ministry on Thursday set up a fund to encourage wine tourism in France, promising to invest "several hundred million euros" in it.
Vinexpo, which started in 2006, alternates between Bordeaux and Hong Kong.
Some 2,350 exhibitors from 42 countries will promote wines and spirits to 45,000 importers and other wine-trade professionals from 120 countries this year.
France is the world's largest wine producer and the sector employs 500,000 people.
But long-established producers face challenges from New World producers and changes in drinking habits at home and abroad.
Hollande, who was met by Vinexpo president Xavier de Eizaguire and the mayor of Bordeaux, Alain Juppé, a member of the right-wing opposition Républicains, who hopes to stand for the presidency in 2017.