One of the most emblematic promises of Francois Hollande's presidential campaign was to partially reverse the increase of the retirement age from 60 to 62 under his predecessor Nicolas Sarkozy.
Thursday’s change applies only to those who started to work at 18 or 19 years old and paid into the national pension scheme for at least 41 years.
According to the government, the measure makes 28,000 people eligible to retire this year and 100,000 people every year that follows, fewer than the Socialists implied during the election campaign.
The measures will cost three billion euros over five years. The government plans to make the sum up by a raise in retirement contributions by employers and employees.
Sarkozy's government increased the retirement age in 2010, sparking weeks of nationwide strikes and protests.