On 13 April 1975, a military coup d'état deposed and killed Chadian president François Tombalbaye, replacing him by a military council.
The most important factor leading up to the coup was a growing sentiment of distrust towards Tombalbaye inside the Chadian army. This distrust was exacerbated by the president's planned purge of the military cadre. It was also linked to the army's incapacity to deal with the ongoing rebellion waged by the FROLINAT, FAN and related insurgent groups.
There are strong indications of French involvement in (or at least tacit acceptance and foreknowledge of) the coup, despite French support to Tombalbaye's regime throughout the years.