Among the crowd of mostly young men on May 7 were 29-year-old Adrien and his friend Gregory. It hadn't taken long to register their discontent: both were arrested around the time Macron was on stage in front of cheering supporters at his victory party at the Louvre museum.
“We wanted to go to the Louvre to boo him, but when we saw it wasn't possible we went to Menilmontant where we knew there was a demo planned,” Adrien, a member of the hackers' collective Anonymous, told AFP, referring to an area in northeast Paris.
Groups including anti-fascist Antifa and hooded anti-capitalist activists from the Black Bloc collective were behind the rally, which saw stones thrown at riot police and tear gas fired. Around 140 people were arrested.
Adrien predicts “Paris will be completely blocked” if the 39-year-old president, a former investment banker, tries to implement his pro-business programme which has radical labour market reform at its core.
Macron wants to “impose the American model on France. Our French economic model is at risk of dying very quickly,” Adrien said in a cafe in a town near Paris having been banned from entering the capital.
On the day after Adrien and Gregory's arrests, several thousand protesters from the far-left Social Front group — which had urged voters to reject both Macron and his far-right opponent Marine Le Pen in the election — paraded through Paris, some shouting “Macron resign! One day is enough!”
In his bid to introduce greater flexibility into the workforce, Macron wants French companies to be able to negotiate pay, working time and conditions directly with employees — weakening the national labour code and trade unions.
Only days after he was inaugurated he began negotiations with the trade unions, welcoming leaders to the Elysee Palace for talks.
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Prime Minister Edouard Philippe has said the government will present a bill to the parliament that emerges from legislative elections on June 11 and 18.
It will allow the government, which has said it wants to move “quickly”, to push through reforms by executive order.
Over the past three years, other economic reforms introduced under Macron's predecessor Francois Hollande sparked scenes which have become hallmarks of French democracy: mass street protests and clouds of tear gas.
The previous government's labour reforms — which Macron as economy minister helped draw up but later said did not go far enough — resulted in five months of protests by trade unions last year. Oil refineries were blocked and rubbish piled up in the streets ahead of the Euro 2016 football championship.
Unions led the protests, but far-left activists and anarchists, as well as violent individuals known as “casseurs (hooligans), often hijacked the demonstrations, which routinely ended with serious injuries.
Far-left leader Jean-Luc Melenchon, who finished fourth in the presidential election, has accused Macron of wanting to “destroy” the labour code, saying the plans would encourage a race to the bottom on pay and conditions.
In his victory speech, Macron acknowledged the divisions and anxieties of French society which deepened during a vicious election campaign.
“I will bring us together and reconcile us because I want our people and our country to be united,” he told thousands of supporters at the Louvre.
And on the campaign trail, he spoke regularly of the need for France to be “soothed”.
But calming the country must be balanced with his other priority: implementing his programme, which he has said he will do with presidential decrees if needed.
“I will not reverse course on any of the commitments taken in front of the French people,” he said as he took power on May 14 in comments welcomed by corporate leaders and economists.
The role of trade unions will be critical, particularly that of the Communist-backed CGT, the biggest union nationally.
The unions have long lost their ability to paralyse the country, but are still capable of mobilising their troops in large numbers.
The head of the CGT, former car worker Philippe Martinez, has raised the spectre of protests already, while his counterpart at the more moderate and reformist CFDT, Laurent Berger, has urged Macron to take his time.
“If the government wants to force this through or doesn't take into account some of the proposals we have put on the table, obviously there'll be anger and perhaps demonstrations,” Martinez told Europe 1 radio on May 22 as negotiations with the government began.
Jean-Marie Pernot, a researcher at the Institute of Economic and Social Research (IRES), said the unions are playing wait-and-see.
“The big unions don't yet know what line to take with Macron. I doubt they are going to join the Social Front,” he said.
Economist Gilbert Cette, a labour market specialist at the University of Aix-Marseille who favours the reform, believes the parliamentary elections are pivotal.
If Macron wins a majority with his new centrist party Republique En Marche (Republic on the Move), he will have an indisputable mandate to press ahead with his plans.
“We've become accustomed to people getting elected in France and then doing something completely different,” Cette told AFP.