France has become the latest country to send out a warning to tax evaders, after declaring it had secured a list of 3,000 citizens who had about €3bn in Swiss bank accounts that is suspected to have been undeclared. If offshore accounts are not declared, or a penalty not paid before a government amnesty on criminal investigations closes at the end of the year, some of the country's wealthiest citizens could be faced with legal action, the Financial Times reports. 'This is not an empty threat,' said Sebastien Proto, chief of staff at the budget ministry. 'We are getting more and more information and protection is falling. Bank security is being rolled back.' The news comes at the same time the government is increasing its campaign against tax fraud and preparing to call banks to account over their practices in the financial services industry. Last week, France signed a tax treaty with Switzerland that will allow more transparency for authorities to get information on suspected tax offenders.