President Emmanuel Macron wants to simplify France’s unwieldy pension system, which comprises more than 40 different plans, many with different retirement ages and benefits. Macron says the system is unfair and too costly.
He wants a single, points-based system under which for each euro contributed, every pensioner has equal rights.
Past attempts at pension reform have ended badly. Former president Jacques Chirac's conservative government in 1995 caved into union demands after weeks of crippling protests.
Twenty-four years later, the looming standoff is a risky venture for France's hard-left unions who have seen membership and public support wane in recent years.
They are battling to remain relevant against a president who has faced down waves of strikes over reforms of the labour market and SNCF railways.
For Macron, the showdown will set the tone for the second half of his mandate, with more difficult reforms to come, including to unemployment benefits.
The strikes follow months of sometimes violent "yellow vest" over the high cost of living and perceived elitism of political class.
Laurent Berger, head of the reform-minded CFDT union, said the social environment was more explosive than in 1995.
"In terms of tension, social cohesion and fractures within society, it's a lot worse now," Berger told reporters.
