Results posted at Companies House for 2015 show the firm lost £69m, compounding its £217m loss in 2014.
Chairman and chief executive Bruno Dupety blamed problems with a small number of legacy contracts, thought to include the fallout from the Nottingham tram scheme.
He said: “In view of our poor financial performances in 2014 and 2015, the group has launched an enterprise inititative focused on the basics of our business and of our group: quality and precision in the production process of our construction sites and focus on profit.”
He added: “We envision the benefits and rewards from this plan will be gained from 2016 onwards.”
Revenue fell from £1.1bn to £935m over the year.