Syndrome E by Franck Thilliez
After watching an unmarked film he bought from a recently deceased film collector a man goes blind. He contacts his ex-girlfriend, a local detective, and she promises to look at the film and into its origins. As she begins to dig into the history of this bizarre film from the 1950s people she has questioned are being silenced, in gruesome ways. Enter Inspector Franck Sharko, a very damaged man and brilliant profiler for the Paris police. Together they try to track down the origins of the film, and other possible related deaths, before the same fate befalls them.
Starting in France and moving to Belgium, Cairo and Quebec, this is a compelling mystery with the dark history of neuroscience at the center.