Mézard "strongly condemned" the incident in which the contents of seven tankers was emptied onto the ground overnight in a town in south-west France.
The wine was both French and Spanish, according to the French Ministry of Agriculture.
While he understood the "exasperation of some French wine-growers, who are experiencing real difficulties", Mézard said that "violence has never and will never help to resolve them".
Motorways, border blocked
Hundreds of wine-growers have blockaded motorway toll booths and the border this week in protest at what they see as unfair competition from cheap Spanish wine.
Spain has expressed concern over such protests, which have been taking place for over a year.
Top officials from both countries' agricultural ministries met in Madrid to discuss the crisis on Wednesday and decided to set up a joint committee of representatives of the sector.
The first meeting will take place in Paris on 25 July.
French winegrowers are to meet local officials next Monday and officials from Mézard's office soon after that.
EU subsidies scrapped
They complain that Spanish growers can undercut them due to lower costs and variations in regulations, especially over the addition of concentrated grape must during winemaking.
They also want the European Union to restore subsidies for the production of concentrated grape must.
After the subsidy was scrapped in 2008 many Spanish producers went over to making cheap wines, putting them in competition with their colleagues in south-west France.