Farmers in France blocked roads into Paris on Thursday as they protested against the Mercosur trade deal the European Union hopes to ink with South American countries.

Scores of tractors were driven into the capital before dawn with a number managing to get through to the Eiffel Tower and the Arc de Triomphe.

The farmers managed to overrun checkpoints and entered the city while being swarmed by police.

The French government said it would "not stand by" and allow "illegal" actions.

Government spokeswoman Maud Bregeon told France Info Radio that blocking a motorway or "attempting to gather in front of the National Assembly with all the symbolism that this entails is once again illegal," adding the government "will not allow it."

Why are farmers protesting?

The protest — largely-led by the Coordination Rurale union — takes place amid fears that the planned free trade deal with the South American Mercosur bloc could flood European markets with cheaper imports.

"We are between resentment and despair. We have a feeling of abandonment, with Mercosur being an example," Stephane Pelletier — a senior member of the Coordination Rurale union — told the Reuters news agency beneath the Eiffel Tower.

"We said we'd come up to Paris — here we are," said Ludovic Ducloux, co-head of one of the union's chapters. 

One of them bore the message "No To Mercosur", referring to the deal with four South American nations. 

Aside from the trade deal, farmers are also upset over a government decision to cull cows in response to the spread of nodular dermatitis — a bovine sickness widely known as lumpy skin disease.

German farmers also demonstrating

German farmers were took to the country's highways over the Mercosur deal, parking up tractors at motorway junctions in parts of the country.

German news program Tagesschau reported that farmers had blocked motorway entrances to the A4 in Thuringia and the A9 in Saxony-Anhalt.

Demonstrations were also expected in Mecklenburg-Western Pomerania and Brandenburg.

What is the Mercosur deal?

The free trade deal aims to bolster trade between the South American and European economic blocs, but is viewed critically by a number of EU member states.

Those backing the agreement include Germany, Spain and Nordic countries who argue that it increases exports currently suffering under US tariffs and reduces reliance on Beijing.

However, critics including France, Italy and Poland are wary of an influx of cheap commodities and its impact on European farmers.

Farmers in Belgium staged mass protests against the trade deal in December when they rolled hundreds of tractors into Brussels.

EU member states are expected to vote on the trade accord on Friday, with the deal piling pressure on President Emmanuel Macron and his centrist Ensemble coalition, which does not hold a majority in parliament.

On Thursday evening, Macron announced on social media that France would vote against the agreement on Friday.

However, since the European Commission secured Italy's support, it is likely that the agreement will be adopted during Friday's vote.

Edited by: Wesley Rahn