The right to access to EU documents is one of the rights the beneficiary of which are (but not only) EU citizens. This right is not listed in the fundamental rights catalogue of EU Citizen under Article 20 of the Treaty on Functioning of the EU, but is enshrined in Article 15(3) TFEU and Article 42 of the Charter of fundamental Rights of the EU; thereby it is not only an EU fundamental right but an EU principle as well.
These primary EU law provisions are specified in Regulation 1049/2001. This right is of interest to both academic and legal practitioners, namely of those involved in private law enforcement of EU law-based claims (e.g. competition); therefore it is a subject to very dynamic case-law of the EU Court of Justice.