Joel Domenjoud knows he sounds paranoid, but recent events have made him reconsider what his government is capable of.

Last month, one day after the environmentalist filed an official request for France to lift the ban on the Paris climate marches that had been months in the making, Domenjoud got a phone call from police saying he was being put under house arrest.

That morning, Domenjoud said he had noticed a man and a woman following him, about 15 meters behind. He jumped on a bus and took the Métro into Paris where he waited for news at a friend's house. At 3 pm his neighbor called saying their apartment building was full of police looking for him. By 4:30 he was signing his house arrest papers at the police station.

Domenjoud is one of at least 24 activists who had their movements restricted by the government for allegedly defying a ban on protests that France enacted in the wake of the Paris attacks last month.

Climate activists around the world were already worried about police surveillance: all it takes is a missing computer file or a malfunctioning smartphone to get them wondering if they're being hacked by the government.

What's different for climate activists organizing protests around the COP21 is that France's new state of emergency doesn't distinguish between legal activism and terrorism, making them targets of raids and arrests before they've done anything illegal, said Juliette Rousseau, an organizer with Coalition Climat 21, a group representing a range of activists from the radical left to the World Wildlife Fund.

"We know we're being watched. Most of us already have an 'S' note on our government files, which means we're being surveilled by the [French] state," said Rousseau.

During a phone interview, Rousseau tells VICE News she can see a police officer "dressed as an average hipster" walking in front of her. She says she met with him before the COP21 began.

"When I started [organizing] six months ago, [the police] told me they would like to go for a drink with me. When I arrived, there were two of them…. The first question they asked was 'are you not scared?'" says Rousseau.

The officers reassured Rousseau that she had no reason to be afraid and they were just asking out of curiosity. "But it sounded a bit like a threat," she says.

All of this is normal procedure, says Rousseau. The officers are part of the police service's information gathering apparatus. They attend events and meetings, and they have a reciprocal relationship of asking for information, she says. "I choose what I want to tell them and what I don't," she says.

Rousseau says she isn't against police being in the activist space because it's open to the public. "I don't think they are the problem," she says.

The major concern is that the French Parliament voted to enact a state of emergency that is much too wide, says Jean-Pierre Dubois, the honorary president of the French Human Rights League. It confuses the normal democratic actions of citizens with the crimes of terrorists and it's a very serious problem, he says.

Last month, France's parliament voted to extend the state of emergency for three months, allowing the government to immediately place any person under house arrest if there are "serious reasons to think their behaviour is a threat to security or public order."

It also gives the government the ability to dissolve groups that it considers to be a threat to public order and put members of these groups under house arrest.

France's prime minister, Manuel Valls, addressed parliament before the vote, saying the security measures were "the efficient response of a democracy, a free country."

"We're at war," he added.

Domenjoud is one of the most visibly affected activists by these measures. While he has committed no crime, he is on a loose form of house arrest. He can go anywhere in Malakoff, a suburb south of Paris, but he can't pass its borders. He also has to check in with police three times per day and can't leave his apartment between 8 pm and 6 am.

He says he doesn't know how police keep track of him, but he's pretty sure they know where he is as long as he's carrying his phone.

He says police appear to know when he's planning to leave his apartment because he could see them waiting on the street outside his apartment. "From the moment I put on my jacket, they were waiting. The worst part is thinking about if my apartment is being listened to," he said.

Rousseau says she is concerned that activists are being arrested based on their political beliefs. "This is very ideological. And that's where it gets really dangerous," she says.

Once his house arrest is over on Saturday Domenjoud says he won't have much proof that any of this happened. He hasn't been charged with a crime so he doesn't need to appear in court. But he doesn't plan to let his ordeal go without a fight.

"I will have lost part of my life these 15 days. It's very important that this situation does not become normalized," says Domenjoud.

He says he plans to take his case all the way to the European Court of Human Rights if he needs to. He will take the next step in his legal battle tomorrow by filing an appeal with the French state council.

"They have not chosen a good one. I know very well my rights," he says.