Urban art is, by nature, ephemeral, rebellious, and often free. Yet when it crosses the threshold of a gallery or an auction house, it becomes a financial asset subject to strict validation rules. How can a movement born out of illegality guarantee the authenticity of its works? This is the paradox of street art. Today, investing in contemporary urban art requires constant vigilance, as the risk of encountering a disputed or questionable piece has never been higher — particul

Updated on 6 January 2026 The California-based auction house Julien's Auctions has announced, with heavy promotion on social media, a sale of works by the street artist Invader at the end of September. The sale mainly consists of mosaics that were torn down from the streets, either in the French Basque Country or in Paris. One of the emblematic works of the BAB invasion, BAB_07 , installed on the Grande Plage in Biarritz, precisely on a boundary wall of the famous palace, the