He was convicted of the kidnapping and murder of 8-year-old Philippe Bertrand in January 1976.The trial began on 18 January 1977 and he was defended by Robert Bocquillon and Robert Badinter.
A contentious issue in the trial was the validity of capital punishment in France; Badinter, a fervent supporter of its abolition, would ultimately convince the jury not to execute his client.
This case is said to have had an influence in leading to the abolition of the death penalty in France in 1981.
Henry was instead sentenced to life imprisonment and was paroled in 2001; however, he returned to prison two years later after having been caught trying to smuggle drugs into France.