Alstom Network UK Ltd. was fined 15 million pounds ($19.3 million) after being found to have used a bribe in an attempt to win a Tunisian tram-and signaling-contract.

The U.K. subsidiary of the French rail company was sentenced by a London judge Monday after being found guilty of conspiracy to corrupt last year. The conviction stems from a 2.4 million-euro payment (2.6 million) to a Canadian shell company, which turned out to be a front for a firm controlled by the brother-in-law of the country’s ousted president, Zine El Abidine Ben Ali.

The conviction concludes the Serious Fraud Office’s 10-year investigation into Alstom Group’s U.K. unit. Three executives from the energy unit were jailed last year for bribing Lithuanian politicians for a $240 million power station contract, leading SFO Director Lisa Osofsky to say the group had a widespread culture of corruption. General Electric Co. bought the unit in 2015.

The SFO’s attempts to pursue Alstom’s U.K. rail subsidiary have been less successful. Only the Tunisian case has resulted in conviction, with the company and its executives being acquitted of all bribery charges relating to other contracts won in Hungary, Poland and India.

The company was also ordered to pay 1.4 million pounds in legal fees. Both payments have to be transferred within 28 days. Alstom declined to immediately comment on the fine.