They used a heavy tractor to break down a massive access gate and set fire to tyres and straw bales on the authority’s premises.
French media reported that there were arrests and that at least one police officer was injured.
Massive protests in the central French city of Clermont-Ferrand led to violent riots last month.
Farmers are demanding a “balanced and fair” Common Agricultural Policy (CAP).
Cattle farmers in particular fear EU agricultural reform currently being negotiated will result in significant losses in income transfers.
Franck Leprêtre, President of the FNSEA Center-Val de Loire, said: “According to our estimates, with this reform we will lose around 80 euros per hectare; that’s 52 million euros for agriculture in the Center-Val de Loire.”
Mr Leprêtre fears that many farmers will not be able to adhere to the new organic regulations.
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Further demonstrations and blockades are scheduled to take place across the country in the coing days.
France’s Agriculture Minister Julien Denormandie is under growing pressure to stop the EU from accepting any further concessions which could harm the livelihoods of French farmers.
The new policy being debated in Brussels seeks to move more money from traditional direct payments into rural development, and place more obligations on farmers to engage in environmental improvement and innovation.
A new national strategic plan is being drawn up as France’s contribution to the ongoing EU debate about CAP reform.
The FNSEA wants coupled production supports retained for some sectors, especially livestock, and to prevent additional transfers of money.
