Alstom, the cash-strapped French engineering firm, has warned investors to act with "extreme prudence" after confirming reports in Financial News that it had received a takeover approach from a mystery Dutch bidder.

In a formal stock exchange statement, Alstom said it had been approached by MJ Global Acquisition "communicating its wish to acquire the whole Alstom capital" at a price of €2 a share, valuing the company at €563m ($624m).