A London court has ordered Alstom Network UK Ltd. to pay 16.4 million pounds, or $21 million, for a bribery scheme in Tunisia, bringing to a close a decade-long corruption investigation that spanned the globe.

The London-based subsidiary of French transportation company Alstom SA was convicted last year of conspiracy to corrupt and ordered Monday in Southwark Crown Court to pay 15 million pounds in fines, or $19.2 million, and nearly 1.4 million pounds in costs, or $1.8 million, within 28 days.

The firm funneled 2.4 million euros, or $2.6 million, in bribes through a shell company to win a 79.9 million-euro contract, equivalent to $88.8 million, to supply trams to Transtu, which operates a public transportation rail network in Tunis, the capital of Tunisia, according to the U.K.'s Serious Fraud Office. The agency also stated that Alstom created fraudulent paperwork to conceal the bribery payments. 

"Alstom is satisfied that, as far as it is concerned, this sentence brings to an end the long-running U.K. proceedings in respect of this historic conduct," the firm said in a prepared statement. 

The company also noted that it was acquitted of three other bribery and corruption charges related to transport contracts in Hungary, India and Poland, as were several of its former executives. 

In 2016, a subsidiary of the firm, Alstom Power Ltd., pleaded guilty to conspiring to bribe Lithuanian politicians and officials and was fined more than $7.7 million and ordered to pay $14 million in compensation and nearly $900,000 in costs. Two employees of the same subsidiary were sent to prison for three to four years for their roles in the scheme.

In the United States, Alstom pleaded guilty in 2014 to paying $75 million to secure $4 billion in projects around the world that generated $300 million in profits. To resolve the case, Alstom agreed to pay a $772 million fine, which was the largest-ever foreign bribery resolution with the Justice Department. 

And earlier this month, a federal jury in Connecticut found a British citizen working in Paris for Alstom guilty of violating the Foreign Corrupt Practices Act and money laundering for paying bribes to officials in Indonesia.

Investigators began eyeing Alstom and its subsidiaries in 2009, when questions arose about the firm's actions in international power and transport projects. The probe involved more than 30 countries, including the U.S., Canada, France, Sweden, Switzerland and Tunisia.

After Alstom was sentenced this week in London, Lisa Osofsky, director of the Serious Fraud Office, said in a written statement that the investigation "shows that we will work tirelessly with law enforcement around the world to root out bribery and corruption." 

Alstom, meanwhile, asserted it had undergone "significant changes" over the past 10 years, "not only structurally and in relation to fields in which it operates, but also in relation to culture and personnel."

The company added it is "committed to being a leading company for the purposes of ethics and compliance, not only in France but also internationally."

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