Joseph Louis Delbrouck, known as Louis Delbrouck, was a French architect and socialist activist. He took part in the 1848 Revolution and the Paris Commune. He was a member of the 13th arrondissement section of the International Workers' Association, a member of the federal artists' commission during the Commune, and a captain in the auxiliary engineering legion.

After the revolution of February 1848, he was on the list of candidates proposed by the journal of Victor Considerant's newspaper La Démocratie pacifique for the elections of 23-24 April 1848. He was also a member of the Sainte-Croix-de-la-Bretonnerie club, for which he was charged on several occasions. In 1849, as a representative of the masons' association, he was one of the five signatories of the declaration of principles of a fraternal association of socialist democrats of both sexes, for the political and social emancipation of women.

On 23 August 1849, at the first meeting of delegates from 83 workers' associations to create a Union of Fraternal Associations, he was appointed a member of the five-member provisional committee. Definitively created on the following 5 October, the Union's aims included the mutualisation of labour through interest-free loans and the reciprocal exchange of products, and assistance for children, the elderly and the sick. In May 1850, its directors were arrested and appeared in court on 13 November. Delbrouck, who presented the joint defence, was sentenced to fifteen months in prison. He had read a memorandum at the bar denouncing the irresistible movement of capitalist concentration that was leading to a progressive takeover of all the means of production, and the flagrant iniquity of the legislation that prevented workers from uniting their efforts in a society that constantly referred to the principles of 1789.

In 1863, he was one of the founders of the Société du crédit au travail, which set out to be a savings bank for workers, a mutual credit society for its members and a credit and discount bank for cooperative societies. The following year, in June, together with 27 other citizens, he published a brochure entitled Association générale d'approvisionnement et de consommation. Exposé des motifs, which advocated the abolition of intermediaries.

After the declaration of war in July 1870, Delbrouck was incorporated into the auxiliary corps of engineers and put in charge of external works for the defence of Paris. He was a Captain in the Auxiliary Engineering Legion.

Appointed Knight of the Legion of Honour on 16 January 1871, he refused this distinction "contrary to his republican principles" and because it had been awarded to him by Trochu, who "for four months has done nothing effective to unblock Paris". He also refused to be given command of the Auxiliary Engineers.
A member of the 13th arrondissement section of the International, on 12 March he launched an appeal for the Auxiliary Engineers to join the Central Committee of the National Guard.
A member of the Federal Commission of Artists during the Commune, he also attempted, on his own and on two occasions, to mediate between Versailles and the Hôtel de Ville, succeeding in crossing the lines and then re-entering Paris.

Surprised on the ramparts of Passy on 21 May, he was arrested and imprisoned in Versailles. His case was dismissed, but he was very ill and died on 16 July 1871 at a friend's house in Versailles.