* France on high alert after bin Laden speech targets France
* French burqa ban, Afghanistan military role under fire
* Aggressive policing, law, intelligence gathering helps
(Story repeated from Tuesday night. No changes to text)
By John Irish and Nick Vinocur
PARIS, Nov 23 (Reuters) - Aggressive intelligence gathering and some of the toughest anti-terror laws in Europe have helped France thwart Islamist terror attacks for 15 years, but a new call to arms by Osama bin Laden has the country on high alert.
Unlike Britain and Spain, France has never been attacked by al Qaeda at home, despite being a NATO member that took part in the invasion of Afghanistan and still having troops there.
Yet fresh tensions over Afghanistan, France's ban on full-length Islamic veils and bin Laden's picking out of France as a specific target have alarmed security officials who say the risks have never been so high for the French.
"It is a period that will be tough," a source close to the defence ministry told Reuters. "It is more worrying this year than ever before. It's not bluff, it's not politics."
Bin Laden's speech last month backing the kidnapping of a group of French people by al Qaeda's North African wing, AQIM, and a separate warning to Paris from that group last week, have fanned tensions ahead of Christmas and as France prepares to host high-profile G20 gatherings next year.
Too isolated today to launch his own attacks, bin Laden can still easily mobilise militants faithful to him, and his message aired on al-Jazeera television last month will be read as a green light for a French attack, intelligence sources say.
Potential targets include nuclear power plants, the undersea Channel Tunnel to Britain and Paris's transport network, which was struck in 1995 by Algerian militants in a metro station bombing that was the country's last terrorist attack.
"(With) an average of two fairly serious attacks being thwarted each year, well, one of them will eventually succeed," said Francois Heisbourg, a senior security expert at the French Centre for Strategic Research (CFRS).
For a timeline on past attacks, click on [ID:nLDE6AM27X]
AQIM: BANDITS OR MILITANTS?
Europe is on a constant watch for threats, particularly since the 2008 Mumbai attacks. France has been on "red" alert, the second-highest on a scale of four, ever since the 2005 London bombings.
In recent weeks, hoax calls have prompted Eiffel Tower evacuations, and France's intelligence chief Bernard Squarcini has warned that "red lights are flashing" like never before.
France's big worry now is AQIM, (al Qaeda in the Islamic Maghreb), a group of mostly Algerian-born militants, who have carried out small-scale attacks including the recent abduction of seven foreigners, including five French people, in Niger.
AQIM's origins lie in the Armed Islamic Group of Algeria, or GIA, which was behind several bomb attacks in France in 1995-96.
Loosely affiliated to bin Laden, AQIM has some 200 members who fled to the Sahel deserts from Algeria after years of internecine conflict. They behave more like bandits, flaunting stolen SUVs and rifles in photos, than fanatical militants.
In an audio message released before last weekend's NATO summit, AQIM said France must withdraw from Afghanistan if it wants its hostages released. In a first for the group, it also said Paris should negotiate only with bin Laden.
"These guys used to just be big bandits," said Alain Chouet, France's chief of external security from 2000-02. "The publicity around al Qaeda means that in Muslim countries there is more gain in wrapping yourself in the al Qaeda flag."
While AQIM has few direct links with France, experts say that with back-up it could effort some kind of symbolic operation. An intelligence source noted AQIM's leaders speak French and could easily connect with North African immigrants.
PATH TO TERROR
Despite past differences with Washington and London over Middle East policy, France has long been a target for Islamic terrorists because of its colonial history in North Africa and problems integrating its huge Muslim minority.
Numbering five million, France's Muslim community is the European Union's biggest, but many are marginalised in grim city suburbs and poor housing estates with poor job prospects.
President Nicolas Sarkozy's ban on the burqa smock that veils the face and body has enraged many Muslims, and bin Laden condemned the law in his October message. [nLDE69Q1O8]
Government sources say about 25 French nationals, including converts to Islam, have travelled to northern Pakistan and Afghanistan for training and indoctrination, having become radicalised in Egypt, Saudi Arabia or Yemen.
In a case that highlighted the underground recruitment process, six Frenchmen and an Afghan were jailed in 2009 for trying to recruit jihadists at a Paris mosque to go to Iraq.
"This sort of foreign experience is absolutely necessary to deepen radicalisation and create hardened warriors," Heisbourg said. "Without it, you have inept jihadists."
Under close watch by security services, such militants pose a threat to France if they go off the radar, a source said, even more so than established underground cells.
Five terror suspects were arrested this month in Paris for conspiring to launch attacks. One had travelled to Afghanistan.
"When we have five million Muslims in the country ... if we have one in 10,000 that decides to turn to violence that makes for a healthy reservoir," Chouet said.
POLICE STATE, LEGAL SYSTEM
France's success dodging major attacks is in large part due to its water-tight security apparatus and legal infrastructure.
The "Renseignements Generaux", now called the Direction Centrale du Renseignement Interieur (DCRI), was set up almost a century ago with a loose and secretive mandate to track radical groups that could harm the state. It now works hand in hand with the DGSE foreign intelligence service.
"Every apprentice dictator envies it, it's an internal police state that doesn't exist in any other Western country," Chouet said. "While it's not very democratic, the advantage is it has a real expertise in penetrating high risk groups."
This security layer is backed up by some of Europe's toughest anti-terror laws. Authorities have expelled dozens of Islamic clerics for inciting religious hatred, something that can take years in Britain.
French investigating magistrates have far-reaching powers and can approve search warrants or order wiretaps. People can also be arrested under broad "suspicion of conspiring in relation to terrorism" legislation, enabling authorities to hold and question a person for the smallest concerns.
"Generally, they are released, but the law weighs on the individual and helps prevent attacks." Chouet said. (Editing by Catherine Bremer)
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