PARIS, France — Time is on Guy Robert’s side: Since he retired at age 60, he’s using his new freedom to turn back the family clock and trace the paths of his ancestors, from a 17th century royalist to grandparents who resisted the Nazis in World War II.

Still vigorous and healthy, he feels he has gained back years of life — like his newly retired, 59-year-old sister, who now dons a cowboy hat and boots for square dancing lessons.

“What happiness!” says Robert, now 61. “To retire at 60, in good health, allows you to discover things. After working since the age of 18, “I retired with a sense of great joy and liberation.”

Robert wants his son and daughter to share in the bounty by retiring at 60, too.

President Nicolas Sarkozy says that dream is unrealistic and is in the midst of changing France’s pension system to increase the retirement age to 62. Even that is still far short of other rich countries such as the United States and neighboring Germany, which have raised retirement ages.

But Robert and his family joined a protest march through Paris on Thursday against the unpopular reform that has brought massive nationwide street demonstrations and two weeks of strikes.

Aging populations make retirement 60 an increasingly costly privilege, with the ratio of retirees to workers growing and other countries raising their retirement ages. But in a country where people cherish the good life and leisure time, it’s easy to see why people are mad.

Retirement here often means exotic travel, volunteering, taking classes, spending time with grandchildren and hobbies from cooking to hiking to history. Associations for retirees abound.

The Robert family, from the Val d’Oise region northwest of Paris, has joined in a last-ditch effort by unions to keep Sarkozy from putting his signature on the pension legislation passed by parliament this week.

But the reform is a centerpiece of Sarkozy’s presidency, and it now seems unstoppable, despite nationwide strikes that at their worst closed all 12 of France’s oil refineries and left one in four gas stations dry.

“I have to protest because I fear my children will live less well than I,” said Robert, who was a finance officer in a mutual insurance concern before retiring.

The protest is a family affair.

Robert’s 58-year-old wife, Marie-Helene, an accountant, calculates that she will have to work nine extra months, until Jan. 2013, if the reform, which is to be introduced gradually until 2018, becomes law.

Robert’s 29-year-old daughter, Melanie, is morose. She is employed by the National Retirement Fund “so I know how it works.”

Will she ever profit from retirement like Aunt Nicole, whose life was transformed when she said goodbye to her job in property management last year, at age 58?

Robert’s sister, Nicole Rateau, a widow, has taken up square dancing and painting and just returned from a group trip to the western United States.

But the good life is a well deserved one for Rateau. She began working at age 15 and so could retire early at 58.

“To have the good life, we’ve had to work hard to get it,” she said, adding that she must now watch how she spends to be able to enjoy. “It’s the good life on a tight budget.”

Retirement at 60, instituted in 1982, does not always mean full retirement benefits, received only by those who have worked at least 40.5 years, like Robert and his sister. But demographics are conspiring against early outs.

As of 2007, French men could expect to live to 77 and women to 84, an increase of four years for men and three for women since 1990, the national statistics agency says.

This means that by 2020 only 1.5 people will be working, and contributing to the retirement fund, for every retiree — compared to four workers for every retiree in 1960, the government says.

The trend is seen throughout western Europe. In Germany, for instance, the retirement age is now 67.

The pension system in France is complex with 37 different categories with some, like police, able to retire at 55, but the reform also raises that by two years.

Robert, gathered with his family in a small Parisian cafe, contemplates what it means to be “liberated” from the pressures of work and “the need to answer to a boss each morning.”

His eyes light up under a lined brow and a shock of gray hair when he talks about his passion for genealogy, and a search for the family roots that has consumed him since retirement. Robert recounted how, like a detective, he traced the path of his grandparents, Resistance members arrested by the Nazis and deported during World War II. That was just the start.

“I now have time to consult archives on the Internet, and they’ve taken me back in time to 1650 … I discovered a royalist in the family,” he said, chuckling because his own sympathies, like those of his grandparents, go to the French Communist Party.

Having plumbed the family roots, he dreams of discovering the world once his wife retires, and moving to his grandparents’ home near Tours, in the Loire Valley.

“Retirement is the end of work but it’s not the end of your intellectual life,” Robert said. “And it’s because you stop at 60 that you can have it.”