Commemorating the storming of the Bastille on 14th July 1789, Bastille Day takes place on the same date each year. The main event is a grand military parade along the Champs-Élysées, attended by the President of the Republic and other political leaders. It is accompanied by fireworks and publics dances in towns throughout the whole of France.

1789, Storming of the Bastille…..
With les États Généraux (the Estates General), summoned in spring 1789, becoming l’Assemblée nationale constituante (The National Constituent Assembly), and Paris experiencing unrest, the direct cause of this initial uprising of the people of Paris was the dismissal of Necker, a popular Minister, by Louis XVI. On the morning of 14th July, the people of Paris took weapons from les Invalides (L’Hôtel national des Invalides, the National Residence of the Invalids) and headed towards the old royal fortress of Bastille. It was seized following bloody gunfire, and the prisoners released. The King quickly surrendered: he reinstated Necker and acknowledged new Parisian leaders: Mayor Bailly and le commandant de la garde nationale (Commander of the National Guard), La Fayette.
Somewhat famously, Louis XVI asked a French duke that evening if the storming of Bastille was a revolt, with the duke replying “No, sire, a revolution.” At first, the royal response was an attempt to compromise with this new situation. The king arrived in Paris days later, Edelstein says, to declare his support of the revolution and don the tricolor cockade. That event bolstered the revolution’s political meaning and the idea of the storming of the Bastille as a demonstration against political tyranny, rather than a violent event. Feudalism was abolished that August.
1790, la Fête de la Fédération (Celebration of the Federation)……
On 14th July 1790, the demolition of the fortress of Bastille was completed and 260,000 Parisians, along with the King, the Queen consort and delegates from all administrative departments, celebrated the first anniversary of the storming of the Bastille on the Champ de Mars. Known as the Fête de la Fédération, it celebrated the short-lived success of the constitutional monarchy.
1880, 14th July becomes Bastille Day ….
Thereafter, 14th July celebrations were abandoned until, under the Third Republic, the 14th July was declared as a national holiday by the law of 6th July 1880. In order to affirm the recovery of France following the 1870 defeat, emphasis is placed on the patriotic and military nature of the celebration, which begins on the night of the 13thwith the retraite aux flambeaux (a re-enactment of the storming of the Bastille, which sees people carrying torch flames). The following day, church bells signal the military parade. Dances and fireworks conclude the day. 14thJuly has officially been the French Bastille Day since 1880. For the French, it symbolises the end of absolute monarchy and the beginning of the Republic.
Why did the French Revolution happen? ,,,,,,,
There were many reasons. The bourgeoisie—merchants, manufacturers, professionals—had gained financial power but were excluded from political power. Those who were socially beneath them had very few rights, and most were also increasingly impoverished. The monarchy was no longer viewed as divinely ordained. When the king sought to increase the tax burden on the poor and expand it to classes that had previously been exempt, revolution became all but inevitable.
SOURCE Official site of France, and Britanica, Time Mag