Here are some of the law firms in Qatar:

Law Offices of Gebran Majdalany Tel: 442-8899 (office is on C-Ring Road, KAAMCO Building, Opp Toys R Us)
Clyde & Co Tel: 496-7434 (office is located on the 9th Floor Qatar Financial Centre, Westbay)
Patton Boggs LLP Tel:453-2500 (located on the 16th Floor, CBQ Plaza, Dafna Area)
Eversheds - Tel: 496-7396 (no idea where this office is located).
Simmons & Simmons Tel: 483-9466 (located on Al Corniche Street - Al Mirqab Tower, 5th Floor)

Check this website for more law firms in Qatar http://www.hg.org/firms-qatar.html

Best of luck!