Judging from their insignia, they were based on the real-life Euskadi 'ta Askatasuna (ETA).
They wear an iconic white mask, black beret, shirts with symbols on
them, and olive/grey pants. Their hand model features royal blue sleeves
identical to the GIGN hand model with black cloth gloves and dark grey markings (identical to the gloves worn by the Phoenix Connexion and the Professionals).



This separatist group claims the area of northeastern Spain and
southwestern France, in the mountainous region along the Pyrenees,
facing the Bay of Biscay region called Euskal Herria by (Basque
Country). ETA claims on Spanish territory, region called Hegoalde or
South Basque Country, which consists of Álava, Biscay, Gipuzkoa and
Navarre; also claims, in France, the region called Iparralde or Northern
Basque Country, consisting of Labourd, Lower Navarre and Soule.

Source: Counter-Strike Wiki