* Wanted by Swiss, Frenchman arrested in Spain
* Falciani released; ordered to surrender passport
* Lawyer says little chance of extradition
* Speculation of links with Catalan arrest requests (Adds details from court ruling)
By Jesús Aguado and Brenna Hughes Neghaiwi
MADRID/ZURICH, April 5 (Reuters) - Spain's High Court released Swiss bank whistleblower Herve Falciani from custody on Thursday but ordered him to remain in Spain while it considers an extradition request from Switzerland which wants to jail him for industrial sabotage.
Falciani, a French citizen who worked for HSBC's Swiss private bank, in 2008 leaked details of thousands of clients many of whom he suspected were using their accounts to evade tax at home - information that sparked investigations in several countries.
Hailed as a hero by some, Swiss courts sentenced him in absentia to five years in jail. He has been living in France, which does not usually extradite its own citizens, but was arrested in Madrid on Wednesday while on his way to speak at a conference on whistleblowing in the Spanish capital.
Spain's High Court ordered Falciani to hand over his passport and said he must appear before a court every week. If he fails to comply he will be sent to prison, the court said.
France, Austria, Belgium, Spain and Argentina launched investigations based on the information leaked by Falciani, but Swiss authorities insist the data was stolen and therefore legally inadmissible.
Falciani has once before been detained in Spain on Switzerland's request - on a trip in 2012. He was released after the High Court ruled against his extradition, finding the charges he faced in Switzerland were not considered crimes under Spanish law.
His Swiss attorney said the outcome was likely to be similar this time and said the fact he had been released from custody was "confirmation that the case is weak".
"I think the chances he will be extradited to Switzerland are very low. If the chances were high, I don't know why he would have been released, because the risk of fleeing is very high," lawyer Marc Henzelin said.
Falciani's detention comes weeks after Spain's Supreme Court issued international arrest warrants for six Catalan politicians who fled the country after organising an illegal referendum in October and declaring Catalonia independent.
One of them, Marta Rovira, is thought to be in Switzerland.
Newspapers La Vanguardia El Mundo both suggested a possible link between the Catalan cases and Falciani's arrest. A member of anti-austerity party Podemos, Miguel Urban, speculated if the Frenchman had been arrested as a "sweetener" to persuade Swiss authorities to comply with its extradition requests.
When asked whether there was a link, Spain's Justice minister Rafael Catala said the government had no say in the timing of the legal process.
Switzerland's justice ministry declined to say if it had received an extradition request from Spain related to Rovira or any other Catalan politicians.
"Like most other states, Switzerland does not grant extradition for political offences," it said.
"In the event that it receives a request concerning Catalan politicians, the Federal Office of Justice would examine the facts in depth and especially clarify if the allegations against the concerned persons constituted political offences." (Additional information by Emma Pinedo and Rodrigo de Miguel in Madrid; editing by Sonya Dowsett and Robin Pomeroy)