The UN special rapporteur on the situation of human rights defenders, Michel Forst, in his world report for the 20th anniversary of the UN declaration on human rights defenders, includes a number of concerns about Spain.
Among the concerns he cites (starting page 483 of the document below) are the charges against Jordi Cuixart and Jordi Sànchez for rebellion and sedition for protests in Barcelona in September 2017, the "excessive force, particularly through the use of anti-riot equipment and rubber bullets against largely peaceful protesters" reported by defenders and that "defenders of the right to self-determination... have faced increasing restrictions on their activities".
Happy to share w/ you my world report on the occasion of the 20th anniv. of the #UN Declaration on #HRDs. It provides an in-depth analysis of the situation of HRDs in 140 countries. It is only available on my website as OHCHR did not accept to publish it https://t.co/nSMZ65l3KO— Michel Forst SR HRD (@ForstMichel) 18 de diciembre de 2018
Forst "urges [Spain] to fully respect the rights to freedom of expression and assembly, especially for those holding views contrary to the State" given that these are a "fundamental part of the right of participation in a democratic society" and protected by international agreements.
He also asks Spain to adopt strict controls on police's use of force during demonstrations as he remains "gravely concerned by the continued reports [of such incidents] and the impunity with which this is treated". The rapporteur believes that victims should have a "transparent and effective mechanism through which to hold perpetrators to account".