22 September: Prince Frederick informs the city's people that King William I acknowledges their grievances but order needs to be restored, announcing his plan to enter the city the next day, prompting the revolt's leaders to flee from the army.[17]
23 September: Prince Frederick leads the Dutch Army into the city to quell the rebellion.[17]
2–12 August: King William I's troops, sent to recapture the city, only reach Leuven before retreating after the Belgian Government appeals to France for military support, prompting France to send reinforcements under Marshal Étienne Maurice Gérard.
8 September: The inaugural elections for the Belgian Parliament take place, leading to the dissolution of the National Congress.[18]
3 April: The Flemish-minded Nederduitsch Tael- en Letterkundig Genootschap is established.[24]
1843 – Richard de Querelles publishes Le déluge à Bruxelles, the first comic to be published in the city.[25]
1844 – The Belgian-Bavarian friturist Jean Frédéric Krieger [nl], also known as Monsieur Fritz, opens Fritz à l'instar Paris, the first friterie in the city.[26]
4 March: Karl Marx is arrested and expelled after spending three years in the city, where he wrote The Communist Manifesto and contributed to the Deutsche-Brüsseler-Zeitung.[28]
The last public execution is held at the Halle Gate.[1]
21 January: A fire at the Royal Theatre of La Monnaie results in the deaths of three firefighters, leaving only the exterior walls and portico standing.
26 September: Nadar launches the hot air balloon Le Géant from the Botanical Garden. To ensure the crowd's safety, Jules Anspach erects mobile barriers, thereby inventing crowd control barriers.
The Noirauds [nl; fr] children's charity is founded by Jean Bosquet and friends.[45]
The Brussels Zoo closes after going bankrupt and returns the land to the city, which transforms it into Leopold Park.[30]
24 January: The city holds an architectural competition [nl; fr] to boost development on newly available plots along the central avenues created over the Senne.
25 October: The New University of Brussels is established after Élisée Reclus was barred from teaching for political reasons, prompting liberal and socialist faculty members from the Free University to plan an independent institution.
28–29 June: The June Riots [nl] erupt, after a Catholic proposal to rewrite the electoral law in their favour leads to tumultuous parliamentary debates.