Upon achieving independence in 1960, Chad joined former AEF members Central African Republic, Gabon, and Congo in a multilateral military assistance agreement with France. The agreement provided France with use of a major military base outside N'Djamena (then called Fort-Lamy), as well as with automatic transit and overflight rights. In return, France not only was to provide defense against external threats but also was to assist in maintaining internal security in the four countries. Under this clause, Chad or any other signatory could automatically request direct French intervention to ensure the security of its government in the face of insurgency or coup attempts. The French government, however, had the right to honor or refuse requests as it saw fit. Chad also signed a bilateral military technical assistance agreement under which France continued to provide equipment, training, and French advisers in Chadian uniforms. Fort-Lamy continued to serve as a combined army and air-base and was one of the main French installations in Africa from which troops and aircraft could be rapidly deployed to any of the former French African colonies.

Finding it increasingly difficult to stem the rebellion that had broken out in 1965, President Tombalbaye sought French intervention to help restore order. From April 1969 until September 1972, the Foreign Legion and other French units sypplied 2,500 soliders, who joined in operations against the rebels. A mixed regiment was permanently stationed near Fort-Lamy. A limited number of ground attack aircraft, transports, and helicopters supported the Franco-Chadian forces facing the insurgents. As regular Chadian units were formed and exposed to French training, the French forces were gradually reduced.

After Tombalbaye was overthrown in 1975, France's disagreements with the new Malloum government resulted in withdrawal of the remaining French combat forces, although more than 300 advisers to the ground and air forces remained. In 1976 another series of military accords was negotiated covering future French military aid and the transfer of equipment left behind by the French. In 1978 Malloum invoked the guarantee clause of these agreements to ask for renewed French help in stabilizing his regime against the revitalized FROLINAT. French paratroopers and Foreign Legion units returned to Chad in response to Malloum's request but were evacuated two years later at Goukouni's insistence.

In spite of the decisive commitment of Libyan forces in the GUNT offensive of mid-1983, the French were at first reluctant to respond to Habré's urgent request for direct intervention. After further appeals from other francophone heads of state in Africa and from the United States, however, the French launched Operation Manta, a task force of ground troops accompanied by fighter aircraft and air defense systems. Except for several retaliations against Libyan incursions to the south, France avoided direct contact with GUNT insurgents and their Libyan allies. The French presence, however, protected Habré by deterring a GUNT-Libyan offensive south of 16° no8e5 north latitude, where the French forward positions were established.

Libya's failure to honor its commitment to remove its troops followed by a Libyan air attack across 16° north latitude in February 1986, triggered a new French deployment, Operation Epervier. The operation initially consisted of about 1,400 troops, backed by air units continued replenishment brought the total to about 2,500 in early 1987. As of late 1987, most of the remaining French troops were grouped around the capital and at Abéché. The only French forces in Borkou-Ennedi-Tibesti Prefecture were a group of 150 engineers engaged in land mine disposal at Faya Largeau. The French aircraft were based at N'Djamena and protected by batteries of Crotale and Hawk surface-to-air missiles radar units were installed at Abéché and Moussoro to provide early warning.

Although official data were not available, according to one estimate the value of French military assistance to FAN and FANT between 1983 and 1987 was about US$175 million. During the first six months of 1987 alone, all forms of aid, including the expense of Operation Epervier, amounted to nearly US$100 million. This figure included a US$12 million construction program that would enable the N'Djamena air base to handle Boeing 747 cargo aircraft and a project to harden the runway at Abéché to permit its use by fighter aircraft.

Data as of December 1988