Ripstein made his directorial debut in 2015 with "600 Millas", producing the film with Mexican director Michel Franco. The screenplay, by Ripstein and Issa López, was inspired by the ATF gunwalking scandal. In the film, weapons smuggler Arnulfo Rubio (Kristyan Ferrer) works for a Mexican cartel. ATF agent Hank Harris (Tim Roth), who tries to arrest him, is kidnapped by Rubio to bring to his bosses; during the drive, they became friends. Ripstein wanted to focus the story on the two characters, rather than expanding it to include the cartel leaders. He attempted to express his view of guns "objectively, almost like a documentarian", since he has been exposed to guns from an early age; his grandfather took him and his brother shooting on weekends, and "my brother became an exceptional shot; they hunted ducks and my grandmother cooked them". "600 Millas" premiered in the Panorama Section of the 65th Berlin International Film Festival, where it won the Best First Feature Film award (the second consecutive award for a Mexican film; Alonso Ruizpalacios' "Güeros" won the previous year). Ripstein dedicated the award to his son, "who will surely be the fourth generation of our family to make films because he loves it".