Protesters in France have used traditional May Day rallies to demonstrate over proposed reforms to the country's labour rules.
The French parliament is currently debating legislation to allow longer working hours and to ease rules around companies getting rid of workers.
Violence broke out in the capital Paris when some activists threw objects at police, while in the southern city of Marseille workers denounced the bill.
A delegate for the workers union, the General Confederation of Labour, Olivier Mateu, says authorities have been provoking protesters.
"The police are behaving completely irresponsibly. They are carrying out controls, without distinction, and arresting people for nothing. It seems that they are expecting us to explode but we are not letting them provoke us, but everybody will have to take responsibility for what happens."
The government says it hopes the reforms will go some way to reducing France's high unemployment rate, and make the country more competitive by making business more flexible.
In Russia, thousands of communist party supporters have marched on the Kremlin demanding reforms, stopping short of directly criticising Russian President Vladimir Putin.
The leader of the Russian Communist Party, Gennady Zyuganov, says he is confident the national economy can overcome international sanctions and unstable oil prices.
"In order to carry out the state policy successfully, there needs to be at least good financing and a worker should be respected. In this respect our party and the patriotic powers have put forward a complex program leading the country out of crisis."
Events in Turkey have been overshadowed by a car bomb attack in the southeastern province of Gaziantep, in which two policemen were killed and 23 people wounded.
Turkey's Prime Minister, Ahmet Davutoglu has slammed the attack.
"We are opposed to all sorts of terrorism, and we strongly condemn that bloody attack that happened in Gaziantep today. I am deeply sad. I want to express my condolences for the officers, God bless them. I hope the wounded officers and civilians will recover shortly. An investigation has started."
Security was tight ahead of celebrations, with the city of Istanbul having already been attacked twice this year apparently by the self-proclaimed Islamic State group.
Minor skirmishes broke out in the capital Ankara, and at least one Kurdish supporter was detained for chanting slogans favouring the jailed leader of the Kurdistan Workers' Party, Abdullah Ocalan.