Chad’s transitional military authorities and rebels has signed an agreement for a national dialogue, in Dohar after months of mediation by Qatar.
But the main rebel group, the Front for Change and Concord in Chad refused to sign the deal.
It had insisted Mr Déby excludes himself from elections.
He took over the leadership of the country last year after his father, Idriss Déby, died while on the front line fighting rebels.
Meanwhile, Elections are due to take place in October.