As on previous protest days, there were scuffles between police and protesters across the country, while demonstrators also stormed the headquarters of French luxury goods firm LVMH in Paris.
All eyes on Friday will turn to France's Constitutional Council, the country's highest administrative authority, which will announce its final say on the pensions legislation in the final hurdle before Macron can sign it into law.
Police expect around 400,000 to 600,000 people to take part nationwide on Thursday. That would be fewer than half the nearly 1.3 million who demonstrated in March at the height of the protests against the reforms, which include raising the retirement age from 62 to 64.
"Now's not the time to give up, because that's what Macron is expecting", said Johan Chivert, a student in the Creuse region in central France.
"We have to keep going and show the people are against this reform."
Security forces were on alert, with around 1,500 anarchist and radical protesters expected in Paris, while regional towns such as Nantes and Rennes are again seen as being at risk of clashes.
"The decision from the constitutional court on Friday will bring an end to the democratic and constitutional procedures," Macron told reporters on a trip to the Netherlands on Wednesday, adding that public debate "will continue, for sure".
If the court issues a green light -- as ministers are privately confident it will -- Macron hopes to sign the changes into law immediately, clearing the way for them to enter into force before the end of 2023.
Having repeatedly snubbed calls for talks with union leaders in recent weeks, the 45-year-old leader said he would invite labour representatives for discussions once the court decision was published.
If the law is approved, it remains to be seen whether unions will call more strikes, with momentum clearly waning and employees reluctant to sacrifice salaries for what seems like a losing battle.
Most trains will be running on Thursday at state rail operator SNCF and the Paris public transport provider RATP, past bastions of strike participation.
The movement is "far from over", said the head of the CFDT union Laurent Berger as the demonstration got under way in Paris, vowing major protests on the May 1 labour day.
The hard-left CGT union has called for new strikes by refinery workers and rubbish collectors, whose walkout left the streets of Paris heaving with rubbish for three weeks in March.
Workers blocked the entrance to the Feyzin refinery near Lyon for two hours early on Thursday before police intervened, local authorities told AFP. Others blockaded a rubbish incinerator outside Paris.
A Mercedes car and bins were set on fire in the western city of Rennes, while protesters and police clashed in Nantes, a flashpoint of tension in recent weeks.
Protesters briefly occupied the headquarters of LVMH on the glitzy Avenue Montaigne in central Paris and set off smoke flares.
"Mobilisation must continue because this bill cannot see the light of day," Manuel Bompard, a leading lawmaker for hard-left opposition party France Unbowed, told broadcaster France 2 on Thursday.
Increase quantity of work
Surveys show that about two in three French people are against the pension changes, but Macron argues that they are essential to stop the system falling into heavy deficit in coming decades.
Critics accuse the president of riding roughshod over public opinion and parliament, where the minority government invoked controversial executive powers to ram the legislation through without a vote at the end of March.
Speaking in the Netherlands, Macron linked the pension changes to the need for France to control public spending and his wider agenda for closer economic ties between EU members.
"I'm proud of the French social model and I defend it but if we want to make it sustainable, we have to produce more," he said.
"We have to re-industrialise the country. We have to decrease unemployment and we have to increase the quantity of work being delivered in the country. This pension reform is part of it."