Chad uses the Central African CFA franc (XAF). Cameroon, the Central African Republic, the Republic of the Congo, Equatorial Guinea, and Gabon also use it. While technically distinct from the Western African CFA franc (XOF), the two currencies are used interchangeably at par in all CFA franc (XAF & XOF)-using nations.
The French treasury backs both CFA francs, which are linked to the euro at €1 = XAF655.957.
Bringing foreign currency into Chad is not restricted. Payment in US dollars and euros is often accepted immediately.
There are Ecobank ATMs in Chad where you may withdraw cash with a master card or visa card. For a complete list of locations, see the Ecobank website.