PARIS, Jan 8 (Reuters) - French farmers have brought tractors to central Paris and blocked roads across the country to demand government action to address numerous grievances.

Here are some of the issues that have prompted the protest movement and initial responses at government and European Union levels.

WHY ARE FARMERS PROTESTING?

Farmers in France, the EU's biggest agricultural producer, say they struggle to make a profit due to high costs and excessive red tape while facing unfair competition from countries within and outside the EU that do not have to meet the same strict production standards.

MERCOSUR

A proposed trade deal between the EU and the South American bloc Mercosur has been a focus of discontent among farmers in France and across Europe. They say the arrangement would lead to cheap imports of South American commodities, notably beef, ethanol and sugar, that do not meet EU standards.

The agreement, which could be signed next week, includes a significant section on agriculture with the establishment of import quotas for certain farm products from Mercosur countries - Argentina, Brazil, Paraguay and Uruguay - either duty free or at reduced levies.

On the other hand, the deal would also give EU farmers increased access to South American markets, which could boost exports of products such as wine, cheese and olive oil.

Even though Paris has won significant last-minute concessions, including safeguard measures on sensitive farm products such as beef and sugar, the government and farmers still oppose the deal, claiming imports should be produced with the same standards as EU produce.

French Agriculture Minister Annie Genevard said France would continue to fight against the deal in the European Parliament, where it also needs to be approved.

CATTLE DISEASE

Some French farmers, mainly in the south of the country, also blame the government for its handling of the lumpy skin disease affecting cattle, including the culling of entire herds when the highly contagious virus is detected.

Lumpy skin disease, mainly spread by biting insects, causes fever and painful skin lumps, weakens animals and reduces milk output.

The government, which said that the disease could wipe out about 10% of the national herd if left unchecked, has launched a campaign to vaccinate all cattle in affected regions.

ENVIRONMENT, RED TAPE

On the environment, farmers take issue both with EU subsidy rules and what they see as France's overcomplicated implementation of EU policy.

They say France applies tougher restrictions than other EU member states, including a ban on a pesticide for sugar beets and taking a highly bureaucratic approach to water use and fertiliser pollution.

Green policies are seen as contradicting goals to become more self-sufficient in the production of food and other essential goods in the light of Russia's invasion of Ukraine and amid trade tensions with the United States and China.

ECONOMIC DECLINE

Farmers see an excessive regulatory burden as contributing to a decline in French agricultural output, exports and income.

France may post its first annual trade deficit for food and farm goods in nearly 50 years in 2025.

Grain growers, previously the wealthiest producers in French farming, have lost money in the past three years as ample global supply has depressed prices while costs for energy and fertilisers have risen.

Pushed by France, the EU on Wednesday agreed to cut duties on imported fertilisers and exempt them from a carbon tax scheme to avert more cost rises.

(Reporting by Sybille de La Hamaide and Gus TrompizEditing by Gareth Jones)