Rioting in France's poor suburbs has highlighted discontent among youths of foreign origin.
The Paris mosque is supported by Algeria
As part of a series on French Muslims, the BBC News website's Henri Astier reports on efforts to build a home-grown version of Islam.
Khalil Merroun's office is open to all. People come to the head of the Evry mosque, south of Paris, for guidance on both spiritual and daily matters.
"I accidentally slammed the door on my kitten and broke his legs," a woman sobs. "The vet says he must be put down."
"He is right," the mosque director tells her. "The Koran allows mercy-killing for animals. I take responsibility for this decision."
Mr Merroun's influence extends far beyond his congregation.
He has been a key player in a long-term drive to establish Islam as a proud religion in France - an effort that has involved rival foreign powers and bitter feuds among French Muslims themselves.
Mr Merroun arrived in the 1960s from Ceuta, a Spanish enclave in Morocco, to work as a technician.
Affable and charismatic, he quickly became a community leader and decided that Muslims deserved better than the murky halls they were praying in.
Kindness of strangers
In the 1980s he secured funding from the Saudi-based World Islamic League. His mosque, completed in 1995, now ranks among the main ones in France.
"I brought Islam out of the cellars in Evry," Mr Merroun says.
In fact, he pioneered a nationwide movement. In immigrant suburbs across France, mosque construction is continuing apace.
Muslims in Villeurbanne still pray in tents, but not for much longer
It is largely fuelled by money from Saudi Arabia, Morocco and Algeria - but also by grass-roots enthusiasm.
In Villeurbanne, near Lyon, a shining new building will soon replace the makeshift tent the faithful currently use to pray.
Azzedine Gaci, the head of the regional Muslim council, insists that the funds were raised locally. "Muslims are richer than they used to be and can afford to give," he says.
The new mosque is being decorated by a local boy who is an award-winning builder. With such commitment, Mr Gaci feels the community does not need foreign help.
"When Saudi Arabia gives you 1m euros with one hand, with the other they give you a list you must or must not say," he says.
According to Mr Merroun, such suspicions are unwarranted. French Islam, he contends, does not have to be beholden to its foreign backers.
Mr Merroun does have a track record of independence. Soon after the Evry mosque was completed, he broke with the Saudis and secured support from Morocco.
Second largest religion
Five million Muslims (estimate)
1,600 places of worship
35% Algerian origin (estimate)
25% Moroccan origin (estimate)
10% Tunisian origin (estimate)
Concentrated in poor suburbs of Paris, Lille, Lyon, Marseille and other cities
"I am comfortable working with the Moroccan Ministry of Religious Affairs because they do not dictate their terms," he says.
But whether or not foreign support for mosques comes with strings attached, national Muslim organisations are clearly far from independent.
One group is headed by the Paris mosque, which is openly bankrolled by the Algerian government.
Another, the National Federation of French Muslims (FNMF) - which Mr Merroun helped found - is backed by Morocco.
The third main group, the Union of the Islamic Organisations of France (UOIF) is an offshoot of the Muslim Brothers, whose roots are in Egypt.
The magnificent Evry mosque was built with foreign money
The three have to work together within the National Muslim Council set up in 2003, and the various regional councils. But rivalries are never far from the surface.
In the northern regional body, the UOIF accuses the Paris mosque and the FNMF of joining forces to marginalise it.
But by far the main rivalry is between the latter two, fuelled by mutual suspicions between Algerians and Moroccans.
The tensions turned violent in Evry in 1996, when a gang claiming links with the Paris mosque briefly took over Mr Merroun's building.
"It was nasty," he recalls. "There was fighting with iron bars." The pro-Moroccan side led by Mr Merroun won both the physical fight and a legal rematch.
Khalil Merroun insists he is his own man
Today both camps are playing down the incident. But the tensions still remain - especially as the Paris mosque has retained the presidency of the national council, despite the fact that the FNMF has a majority in the body.
According to journalist Christophe Deloire, author of the book The Islamists Are Already Here, the notion of French Islam is "a farce".
He describes the country's Muslim community as a "chess board" where foreign forces move their pieces.
"The best way [for Algeria and Morocco] to exert influence on their communities in France is through religion," he says.
France accepts this, Mr Deloire adds, because it needs good relations with its former colonies.
But regardless of tensions at the top, efforts are under way at community level to build a home-grown form of Islam.
Mohammed Ould Kherroub, who heads the Muslim Association of Versailles, west of Paris, deeply resents foreign intrusions that "feed divisions" among Muslims.
Kherroub finds ethnic divisions among French Muslims "intolerable"
"There should be no nationalism. We are all French here," he says.
The Versailles faithful refuse to vote along ethnic lines, and sent blank ballots in elections to Muslim bodies.
His feeling is shared by many across France. The director of the Lille mosque, Rachid Hamoudi, feels confident that one day Muslims will break free from outside powers.
"We must be patient," he says. "Things will change with the emergence of new generations. Eventually we will have really democratic, truly French elections."
Other features in the series by Henri Astier: