Title: Proclamation of the abolition of the monarchy
Content:  During the French Revolution, the proclamation of the abolition of the monarchy (French: Proclamation de l'abolition de la royauté) was a proclamation by the National Convention of France announcing that it had abolished the French monarchy on 21 September 1792.
Title: Kingdom of France
Content:  On September 3, 1791, the absolute monarchy which had governed France for 948 years was forced to limit its power and become a provisional constitutional monarchy. However, this too would not last very long and on September 21, 1792, the French monarchy was effectively abolished by the proclamation of the French First Republic. The role of the King in France was finally ended with the execution of Louis XVI by guillotine on Monday, January 21, 1793, followed by the "Reign of Terror", mass executions and the provisional "Directory" form of republican government, and the eventual beginnings of twenty-five years of reform, upheaval, dictatorship, wars and renewal, with the various Napoleonic Wars.
Title: Louis XVI
Content:  the abolition of the monarchy and the establishment of a republic became an ever-increasing possibility. The growth of anti-clericalism among revolutionaries resulted in the abolition of the dîme (religious land tax) and several government policies aimed at the dechristianization of France. In a context of civil and international war, Louis XVI was suspended and arrested at the time of the Insurrection of 10 August 1792. One month later, the monarchy was abolished and the First French Republic was proclaimed on 21 September 1792. Louis was then tried by the National Convention (self-instituted as a tribunal for the occasion), found guilty of high treason, 
Title: Abolition of monarchy
Content:  One of the most significant abolitions of monarchy in history – along with the Dutch Republic of 1581–1795 – involved the French monarchy in 1792 in the French Revolution. The French monarchy was later restored several times with differing levels of authority. Napoleon, initially a hero of the Republican revolution, crowned himself emperor in 1804, only to be replaced by the Bourbon Restoration in 1815, which in turn was replaced by the more liberal July Monarchy in 1830. The 1848 Revolution was a clearer anti-monarchic uprising that replaced the succession of royal leaders with the short-lived Second French Republic. Louis Napoleon Bonaparte established the Second French Empire (1852–1870), retaining republican aspects while placing himself in the center of the state until the losses in the Franco-Prussian War led to his fall, resulting in the French Third Republic and the definitive end of the monarchy in France. Monarchism, which had held a majority in the National Assembly after the 1871 election, slowly fizzled out over the course of the rest of the century.
Title: History of Europe
Content:  the Citizen, the abolition of feudalism, and a fundamental change in the relationship between France and Rome. At first the king agreed with these changes and enjoyed reasonable popularity with the people. As anti-royalism increased along with threat of foreign invasion, the king tried to flee and join France's enemies. He was captured and on 21 January 1793, having been convicted of treason, he was guillotined. On 20 September 1792 the National Convention abolished the monarchy and declared France a republic. Due to the emergency of war, the National Convention created the Committee of Public Safety, controlled by Maximilien de Robespierre of the Jacobin Club, to act as the country's executive. Under Robespierre, the committee 
Title: List of heads of state of France
Content:  overthrow of the monarchy on 10 August 1792, the Convention included 749 deputies drawn from businesses and trades, and from such professions as law, journalism, medicine, and the clergy. Among its earliest acts was the formal abolition of the monarchy, through Proclamation, on 21 September, and the subsequent establishment of the Republic on 22 September. The French Republican Calendar discarded all Christian reference points and calculated time from the Republic's first full day after the monarchy – 22 September 1792, the first day of Year One. According to its own rules, the Convention elected its President every fortnight (two weeks). He was eligible for re-election after the 
Title: Kingdom of France
Content:  "Citizen King" (Roi-Citoyen). The July Monarchy was beset by corruption scandals and financial crisis. The opposition of the King was composed of Legitimists, supporting the Count of Chambord, Bourbon claimant to the throne, and of Bonapartists and Republicans, who fought against royalty and supported the principles of democracy. The King tried to suppress the opposition with censorship, but when the Campagne des banquets ("Banquets' Campaign") was repressed in February 1848, riots and seditions erupted in Paris and later all France, resulting in the February Revolution. The National Guard refused to repress the rebellion, resulting in Louis Philippe abdicating and fleeing to England. On 24 February 1848, the monarchy was abolished and the Second Republic was proclaimed. Despite later attempts to re-establish the Kingdom in the 1870s, during the Third Republic, the French monarchy has not returned.
Title: Monarchism in France
Content:  In France, Louis Philippe abdicated on February 24, 1848, opening way to the Second Republic (1848–1852), which lasted until Napoleon III's December 2, 1851 coup d'état and the establishment of the Second Empire (1852–1870). The monarchist movement came back into force only after the 1870 defeat by Prussia and the crushing of the 1871 Paris Commune by Orléanist Adolphe Thiers. Legitimists and Orléanists controlled the majority of the Assemblies, and supported Patrice de MacMahon, Duke of Magenta, as president of the Ordre moral government. But the intransigeance of the Count of Chambord, who refused to abandon the white flag and 
Title: Early modern France
Content:  and Malesherbes' resignation in 1776. They were replaced by Jacques Necker. Necker had resigned in 1781 to be replaced by Calonne and Brienne, before being restored in 1788. A harsh winter that year led to widespread food shortages, and by then France was a powder keg ready to explode. On the eve of the French Revolution of 1789, France was in a profound institutional and financial crisis, but the ideas of the Enlightenment had begun to permeate the educated classes of society. On 1792 September 21 the French monarchy was effectively abolished by the proclamation of the French First Republic.
Title: History of France
Content:  legal and all through 1847, there was a nationwide campaign of republican banquets demanding more democracy. The climaxing banquet was scheduled for 22 February 1848 in Paris but the government banned it. In response citizens of all classes poured out onto the streets of Paris in a revolt against the July Monarchy. Demands were made for abdication of "Citizen King" Louis-Philippe and for establishment of a representative democracy in France. The king abdicated, and the French Second Republic was proclaimed. Alphonse Marie Louis de Lamartine, who had been a leader of the moderate republicans in France during the 1840s, became the Minister of Foreign Affairs and in effect the premier in the new Provisional government. In reality Lamartine was the virtual head of government in 1848.

Question: who abolished the monarchy and declared france a republic?
Answer: Convention.
France's Legislative Assembly.