New book on the Law of Street Art "Droit(s) et Street Art” (in French) has been published recently comprising a number of analysis from legal experts in the field.
Description is available here: http://dpc.hypotheses.org/1606,
while the table of contents here: https://f.hypotheses.org/wp-content/blogs.dir/2571/files/2017/07/Droit-et-street-art-Sommaire.pdf
For Latvian-speaking admirers of the topic the article of Mr.Vadims Mantrovs in Jurista Vārds as of 1 August 2017, regarding Street Art, Graffiti and Vandalism, might be of special interest. Available at http://www.juristavards.lv/doc/271108-ielu-maksla-grafiti-un-huliganisms-vandalisms/