Representatives from France's farming union, Confederation Paysanne, told members of the national dairy industry body that milk price cuts had chopped 30,000 producers out of the industry in the last five years.
The move reveals ongoing tension in France's dairy industry, similar to that seen in the UK and other states over the amount of money passed down the supply chain.
The Confederation Paysanne intends to put more pressure on industry officials in the build-up the elections to France's Chamber of Agriculture, which begin on 22 January.
A spokesperson for the union will appear in court at the end January after being charged with breaking into a Nestle factory in 2004.
It is alleged several union members stole around €2,000-worth of dairy products from the factory, equivalent to 27 days of unpaid work by milk suppliers.
A similar but separate attack was launched on a Lactalis factory in the same year. Protestors recently escaped prison, despite being convicted of stealing €3,000-worth of products and handing them out free to local people.
Average milk prices paid to French producers have fallen €0.5 over the last five years, the biggest drop across the 15 pre-accession European Union nations.
The shock has hit French milk producers hard because they were Europe's highest paid.
It has prompted fighting talk from some. "If the government wants to declare war on farmers, we will rise to the challenge and we will continue to victory," said Jean-Emile Sanchez in Montpellier, one of those convicted in the Lactalis break-in.
Milk prices are expected to rise slightly over the next couple of months thanks to more favourable market conditions, namely higher demand.
An industry-wide deal was struck in January 2006 to introduce a recommended national milk price in France, but rows continued with both Lactalis and Sodiaal breaking the agreement in the spring.
Lactalis then reversed its cuts and came back to the table, criticising rival Sodiaal for not doing the same.