France abolished monarchy and become a …

(i) Although Louis XVI signed the Constitution of 1791, he entered into secret negotiations with the King of Prussia. Rulers of other neighbouring countries too were worried by the developments in France and made plans to send troops to suppress the events that had been taking place since the summer of 1789.
(ii) But before this could happen, the National Assembly declared war against Prussia and Austria in 1792. Thousands of volunteers came from the provinces to join the army. They saw this as a war of the people against the king and aristocrats all over Europe.
(iii) The revolutionary war brought losses and economic difficulties to the people. Despite that large sections of the population were convinced that the revolution had to be carried further, as the Constitution of 1791 gave political rights only to the richer sections of society.
(iv) As a result, political clubs emerged. The most successful of these clubs was that of the Jacobins, who belonged to the less prosperous sections of society. Their leader was Maximillian Robespierre.
(v) In the summer of 1792 the Jacobins planned an insurrection of a large number of Parisians who were angered by the short supplies and high prices of food.
(vi) On August 10 they stormed the palace of the Tuileries, killed the king's guards and held the king himself as a hostage for several hours. Later the Assembly voted to imprison the royal family.
(vii) Elections were held. The newly elected assembly, called the Convention, abolished the monarchy and declared France a republic on 21 September, 1792.
(viii) Louis XVI was executed publicly at Place de la Concorde. The queen Marie Antoinette met with the same fate shortly after.