The Parisian flaneur of the 19th century is an urban explorer who wanders around the city, discovering new relationships and stories. The BioFlaneur" is his modern equivalent, set in the future, who uncovers modern stories through bacteria sample scans taken on the city's surfaces. This short film is inspired by the fields of microbiology and synthetic biology and speculates about a future where invisible biological data of spaces and humans is uncovered. Will anything change in our understanding of privacy in public spheres when what's invisible becomes visible?