Socialist presidential front runner Francois Hollande pledged on Friday to renovate crumbling housing and provide better educational opportunities in France's suburban ghettos, denouncing broken promises by President Nicolas Sarkozy.

Visiting the Strasbourg suburb of Meinau, where nearly half the population lives in housing projects, Hollande said Sarkozy had failed to make good on pledges when he won a 2007 election to revive the grim housing estates that ring many French cities.

All public policies - lodging, work, education, security - will be amplified, reinforced in the outskirts of our cities, Hollande said in a speech.

The modern dormitory suburbs of French cities - often home to Arab and African immigrant communities and where social disquiet erupted into mass riots in 2005 - tend to have higher unemployment and crime rates than the cities themselves.

Hollande pledged to renovate 600,000 old buildings per year, which he said would reduce energy bills and create construction jobs for the suburbs' youth.

The issue of suburban ghettos has not been at the centre of the presidential race, given the preoccupations by the French middle classes who are struggling with lower purchasing power, high unemployment and economic stagnation.

Nationwide rioting in tough suburbs broke out in 2005 after two youths were accidentally electrocuted while trying to escape the police. Thousands of cars were torched and hundreds of people injured in three weeks of violence, the worst urban unrest in France for 40 years.

Sarkozy, then interior minister, vowed to get tough on juvenile offenders. When elected president in 2007, he called for a Marshall Plan 2 - a reference to the U.S. aid granted to rebuild post-war France - to offer youth in the most deprived areas paid training and work experience.

Hollande called those efforts a failure, noting that unemployment in the suburbs was double the national average, and ranged as high as 30 to 40 percent for young people.

(Writing By Alexandria Sage; Editing by Daniel Flynn and Robin Pomeroy)