24 Frames was posthumously showed at the film festival that took place during which time frame?
24 Frames (film):  It was posthumously shown in the 70th Anniversary Events section at the 2017 Cannes Film Festival. 2017 Cannes Film Festival: The 70th Cannes Film Festival took place from 17 to 28 May 2017, in Cannes, France.
17 to 28 May 2017