The president of the transitional military council, Mahamat Idriss Déby Itno, signed an agreement in Qatar on Monday with rebel factions on the opening of a national dialogue for peace.
Of the 47 rebel groups represented, 42 have affixed their signature alongside the authorities.
A breakthrough described as "a key moment for the Chadian people" by UN Secretary General Antonio Guterres.
For five months, various Chadian actors have been negotiating under the aegis of the Gulf emirate to put an end to decades of unrest and instability in this country which has experienced several coups.
The signatories of the agreement thus undertake to participate in the national dialogue scheduled for N'Djamena on August 20 in the presence of more than 1,300 representatives from civil society, trade unions, the opposition and those in power.
To the rebel leaders who will go to N'Djamena on August 20, the authorities are offering a ceasefire and security guarantees.
Together during this dialogue, they will have to decide on the organization of the presidential election scheduled for October.