France's elite police units learn to work together

It's almost a year since coordinated Islamist terror attacks in Paris left 130 people dead. Questions remain about how France is preparing to deal with another potential mass attack. The interior ministry has started work that it says will streamline cooperation between the elite police units which respond to such events. Our reporters spent time with one of those units, which was called out in July when two terrorists took hostages at a church in Normandy and murdered an elderly priest.