1988: European Parliament Resolution on Sign Languages
On 17 June 1988, the European Parliament unanimously approved a resolution about sign languages. The resolution suggests that all member states recognise their sign languages as official languages of the Deaf community.
The European Parliament [...] calls on the Commission to make a proposal to the Council concerning official recognition of the sign language used by deaf people in each Member State.
Source: http://www.policy.hu/flora/ressign2.htm