Pope Benedict told a huge crowd yesterday that many in the modern world had turned money, possessions and power into idols that are as false as those worshipped by the pagans of antiquity.

On his second day in Paris, the pope celebrated Mass for more than 250,000 people around Paris' Invalides, a complex of military buildings begun by Louis XIV in the 17th century and which houses the sarcophagus of Napoleon Bonaparte.

The exuberant crowd, many young people who spent the night outdoors and marched from Notre Dame during the night, waved yellow and white Vatican flags as Benedict arrived in a bullet-proof popemobile to say Mass from a tall platform.

In his homily, Benedict, who arrived on Friday for a four-day trip, pursued a theme dear to him: the need to inject lasting spiritual and religious values into a modern society that often seemed enamoured of things material and fleeting.

"Has not our modern world created its own idols?" he said, recalling ancient pagans who worshipped gold and silver statues.

"Has it not imitated, perhaps inadvertently, the pagans of antiquity, by diverting man from his true end, from the joy of living eternally with God," he said, wearing gold, white and red vestments and speaking fluent French.

He quoted the writings of St Paul saying "money is the root of all evil" and added in his own words: "Have not money, the thirst for possessions, for power and even for knowledge, diverted man from his true destiny?"

Towards the end of the Mass, more than a thousand priests dressed in white cassocks fanned out among the crowd with altar boys bearing white and yellow umbrellas to distribute communion to the faithful.

Prime Minister François Fillon, a Catholic, attended the Mass, Benedict's last event in the French capital before he moves on to the shrine city of Lourdes for the rest of the trip.

Since he arrived the pope has been banging the drum about what some see as a resurgence of Catholic identity in France where "laicité", the separation of church and state, is part of the national psyche.

Traditionally Catholic, France maintains a strict tradition of secularism. The French church struggles with a shortage of priests and Sunday Mass attendance is below 10 per cent. But religion has re-emerged as a factor in public life, especially because of the growth of Islam, and French Catholics have increasingly spoken out on social issues.