"The Syrian tragedy will be seen by history as a disgrace for the international community if we do not end it quickly. Aleppo, today, is a martyred city," he told the General Assembly.
The Syrian regime and its foreign supporters are responsible for the crisis, Hollande said, and he urged the UN to take immediate action.
"The Security Council should meet as soon as possible. It should not be a theater of fools ... a place where each evades their responsibility," he said and laid out a road map for a Syria that includes imposing a cease-fire, sending humanitarian aid to Aleppo and other cities, ensuring political negotiations will resume and punishing the use of chemical weapons.
"If we act, there will be more than a solution for Syria, there will be hope for refugees and displaced people," he added.
The French president also stressed the need to act against terrorism that France has experienced in high-profile deadly attacks in Paris and Nice.
"Terrorism prospers from open conflicts,” he said. “No country can say that it is immune to terrorism, fundamentalism and radicalism," he added.
Hollande said France turns to the UN to eradicate terrorism and asked world leaders to make decisions, instead of "just talking about solidarity" in order to meet the challenges.
He also appealed to leaders to speed up and complete the ratification of the Paris Climate Agreement drafted last December.
"We have no time to lose,” he said. "It [the agreement] will only come into force if it is ratified by 55 percent of  countries representing 55 percent of green house gas emissions.”
The U.S. and China, two of the world's largest CO2 emitters, have announced their decision to ratify the deal, while Hollande noted that France will inform the UN on Wednesday that it has completed its ratification procedure.
The French president also addressed energy in Africa and development on the continent.
As two-thirds of Africans currently do not have access to electricity, Hollande said 10 donors have committed to pledging $10 billion for renewable energy in Africa by 2020, while France has taken on 20 percent, or $2 billion, of the total financing.
"Europe has decided on an external investment plan, which might provide $40 billion if member states of the EU would also participate," he added.