O Direito de Matar

I saw this movie many many years ago; but it remained in my mind because of the excellent acting and the suspense. It was a French movie which was about convicted criminals who were awaiting their death. However, in order to make the process more humane, they were not told about the day or time that their execution would take place. At the appointed moment, two guards would rush into the cell grab the convicted criminal by both of his arms and drag the stunned man to the place of execution. The moment when the doors of the cell are flung open with a loud clang and the guards rush in to the overwhelmed prisoner will stay in my mind forever. I would like to hear more about this movie to refresh my mind about the rest of the plot and would appreciate information about it. Thank you.