"It was a bus carrying elderly people," the offcial told CNN.
"There are five people who are injured, and three people safe."
The collision took place on the D17 highway in Puisseguin, near Bordeaux, he said.
According to state-run BFMTV news channel, the crash happened on a single carriageway road, and caused both vehicles to catch fire. The driver of the lorry was also killed.
The bus was carrying pensioners who had just set off from the nearby town of Petit-Palais-et-Cornemps, the channel added.