The two-year contract was signed by Metsu in the presence of Sheikh Hamad ben Khalifa ben Ahmed Al-Thani, the president of the Qatar football federation, during a press conference with other high-ranking Qatari sports officials.
Qatar have little time to waste in preparing for their third match in the final phase of Asian 2010 FIFA World Cup South Africa™ qualifiers in Australia on 15 October.
Metsu knows Qatari football well having coached first division club Al-Garafah in the 2004/05 season.
Metsu resigned as UAE coach on Sunday because of poor results and was replaced on Thursday by compatriot Dominique Bathenay.
The 54-year-old Metsu had been coach of UAE since June 2006 and won the Gulf Nations Cup in January 2007. Previously Metsu had been Senegal coach, leading them to the quarter-finals of the 2002 FIFA World Cup finals in Korea and Japan.