Le site bitfine.biz est-il sûr ?

This appears to be a Ponzi scheme. The company was founded in the UK in June this year. That much is true enough ***** , but that alone does not give any protection to investors. It is not regulated in the UK and investments are not protected. Companies operating in the UK are required to be regulated by the FCA ***** Google street view strongly suggests the address (according to the companies house address above) is a residential address, not a business address. Only one director is registered at companies house, Nick Shaw, and this person is not registered with the FCA in London (there is a car salesman and a letting agent on the register, both outside London).