The assassination of a leftist politician in July, the second such killing in five months, prompted widespread protests, a walkout by opposition lawmakers and calls for Ennahda to step down for failing to ensure security. The Islamist party and its two secular coalition partners finally agreed to step down in favor of a technocratic government.
The new roadmap, however, calls for the Ennahda-dominated assembly to finish writing the constitution in a month, set up the commission to supervise elections and pass an electoral law.
Parliamentary and presidential elections are not expected until early next year.
Saturday's ceremony started three and a half hours late after Ennahda and other members of the coalition refused to sign the roadmap stipulating the government's resignation, preferring to await the results of the dialogue. In the end, all parties except for the left-of-center Congress for the Republic, which is part of the ruling coalition, signed the document committing the government to resign once the technocratic body is set up.
Mediators expressed confidence that the differences would be resolved before talks began next week.