The EU isn't a free market when it comes to agricultural produce at all, thanks to the CAP (Common Agricultural Policy)[1].
E.g. just in the last year[2] central planning for how much quantity of sugar beets each country could produce was finally phased out, with the Dutch expecting in production of up to 25% as a result[3].
This was one of the grand bargains of the EU. In exchange for the likes of France, Spain etc. joining the union they wanted guarantees that these politically sensitive sectors of their economy wouldn't be subject to real competition.
So production in countries like The Netherlands is artificially low since a combination of quotas and other central planning restricts production.
1. https://en.wikipedia.org/wiki/Common_Agricultural_Policy#Equ...
2. http://europa.eu/rapid/press-release_MEMO-17-3488_en.htm
3. https://www.dutchnews.nl/news/2017/01/dutch-sugar-cooperativ...