The Paris-Flash is a magazine. The first page is shown to be green and the last red tinted. The other pages are just white, such as other magazines and newspapers.
The magazine makes many appearances in The Adventures of Tintin, most notably in The Castafiore Emerald, when two reporters for the magazine, Christopher Willoughby-Drupe and Marco Rizotto, show up at Marlinspike Hall and interview Bianca Castafiore, then publish a false article claiming that she and Captain Haddock were engaged.
According to Hergé, he created the magazine after being interviewed for the Paris Match and finding the resulting piece dubious and unsatisfactory.