Mohammed al-Roken was among "UAE 94", when 69 people were jailed on charges of conspiring to overthrow the government in 2013.
The mass trial was criticised by rights groups such as Amnesty International over its process, while accusations of torture were levelled at UAE authorities.
Ludovic Trarieux Award, the prize committee said Roken had devoted two decades to defending fundamental freedoms.
A former head of the UAE Jurists' Association, Roken, 54, was arrested in July 2012, after taking on the defence of several government opponents, including seven Islamists.
Roken was the main point of contact for Amnesty International until his arrest.
The prize jury lamented that Roken's trial had gone ahead behind closed doors and demanded his immediate release.
Amnesty International's Middle East and North Africa deputy director at the time staunchly criticised both the proceedings and the verdicts.
"Not only do the defendants appear to have been targeted simply because of their views, but they have been convicted on bogus charges and denied the basic right to a fair trial," said Hassiba Hadj Sahraoui.
"The only thing this trial shows is the fundamental flaws in the UAE justice system," she added.
Amnesty International also said there were accusations of torture from UAE investigators, the rights of defence were flaunted, and independent observers were barred from the court room.
The annual award, which is worth 20,000 euros ($22,000), recognises lawyers of any nationality who have sought to defend human rights, often at great risk to themselves.
The Luxembourg-instigated European Bar Human Rights Institute (IDHAE), made the award, named after Trarieux, who in 1898 founded France's Human Rights League (LDH).
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