Benoit Joseph Boussu (baptized on April 7 or 8, 1703, in Fourmies — died September 15, 1773, in Avesnes-sur-Helpe) was a notable French luthier known for his distinctive violins, cellos, and contrabasses. His active years spanned approximately from 1750 to 1761 in Brussels. Boussu's craftsmanship was characterized by a unique style that drew upon a variety of regional traditions and historical influences. Evidence suggests that he achieved a remarkable level of skill in luthiery relatively quickly, having embarked on this profession later in life, likely as a self-taught artisan. Dutch luthier and researcher Geerten Verberkmoes (b. 1968) devoted years to studying Boussu's life and work, culminating in a PhD thesis at Ghent University in June 2020. As part of his research, Verberkmoes established a chamber trio named Project Boussu, which performs with replicas he created during his organological analysis; their debut CD was released in 2020 under the Etcetera label.

Before turning to luthiery in his early fifties, Boussu worked as a notary, continuing the profession established by his grandfather and father, Robert Boussu (1673–1729). He practiced as a notary full-time in Avesnes-sur-Helpe for at least 15 years, with preserved notarial records dated from 1733 to 1748. Boussu married his first wife, Marie Charlotte Heisne (ca. 1703–1742), in April 1733; she passed away less than ten years later. In July 1744, he remarried Marie Anne Jugier (ca. 1719–1759). Throughout his life, Boussu fathered fifteen children, but only six outlived him, with four mentioned in his last will: two sons who became silversmiths and two daughters who married a gun-maker and a cobbler, indicating that none of his sons-in-law could succeed him in his craft.

Boussu's entry into violin-making is shrouded in mystery, as he seemingly transitioned to this career abruptly in his late forties. Around 1748, the Boussu family moved from Avesnes-sur-Helpe to Belgium, initially settling in Liège, where he produced his earliest known instrument, a violoncello dated 1749, notable for its quality. Verberkmoes uncovered a notarial document from November 1749 that referred to Boussu as "maitre luthier."

During the mid-18th century, artisan professions were tightly regulated, requiring craftsmen to register with local guilds and complete a mandatory four-year apprenticeship. An alternative path for some was the travailleur libre ("free worker") route, allowing them to work independently without guild affiliation. Boussu's brief stay in Liège—likely under a year—before crafting his first excellent cello suggests he may have undergone only a few months of study and training, which would indicate exceptional talent and dedication. Historical records do contain examples of luthiers who shifted careers or balanced multiple professions, such as German luthier Joachim Tielke (1641–1719), who initially studied medicine and philosophy and was also an art dealer.

By 1751, Boussu had moved to Etterbeek, a suburb of Brussels, as indicated by records from his son's baptism. By June 1753, he was residing within Brussels and had completed at least 37 violins and six cellos, based on serial numbers. Throughout this time, he utilized printed labels bearing the title "Maitre [Me.] Luthier." After 1760, his production notably decreased. Verberkmoes examined city archives, revealing that at least three of Boussu's children died between 1758 and 1760, including a 14-year-old son, as well as his second wife, Marie Anne, who was 40 at the time of her death. Interestingly, none of these obituaries referenced Benoit Joseph's profession, which was customary for individuals in trades.

From 1767 to 1773, Boussu lived in Amsterdam, where he likely focused more on trading musical instruments rather than luthiery. Legal documents from French archives refer to him as a marchand luthier demeurant à Amsterdam ("merchant luthier living in Amsterdam"). The most significant evidence of his craftsmanship from this period is a cittern he made in 1771, the only known example of his work outside the violin family. This finger-plucked instrument, known as the "English Guittar," was particularly popular in the British Isles and France. In December 2015, Geerten Verberkmoes acquired Boussu's cittern from Sworders Fine Art Auctioneers in London. He noted two identical inscriptions in his PhD thesis, with a branding iron stamp followed by handwritten text: Boussu, à | Amsterdam | 1771. Based on his organological analysis and other factors, including the distinctive amber-brown shellac varnish, Verberkmoes asserts that Boussu personally crafted this instrument. Boussu returned to France around late 1772, where he passed away in Avesnes-sur-Helpe at the age of 70.

Instruments Boussu is believed to have produced between 130 and 160 violins and violas, as well as approximately 30 cellos during his most productive years from 1751 to 1761. Of these, around 50 instruments have survived, primarily violins and cellos, along with four violas, two pochettes, one double bass, and the cittern. The Musical Instruments Museum in Brussels houses about a dozen of his instruments, with additional pieces displayed at the Chimei Museum in Taiwan, the Musée De La Musique in Paris, and among private collectors. His work often combined "archaic" techniques typical of local Flemish luthiers (such as a "through-neck" construction using a single piece of wood for the neck and upper block) with more modern designs influenced by foreign makers, like corner blocks, a glued-in bass bar, and necks set at an 85° angle measuring 130 mm in length. Boussu's instruments were consistently crafted, exhibiting dimensions that matched within 1 mm tolerances. Unique features included sides glued directly onto the back plate rather than inserted into a channel and elegantly designed scrolls that consistently featured an additional half-turn.

Labels ☞ (1749–50) Tiny rectangular, handwritten: Boussu, a Liège, 17__

☞ (1751–53) Larger rectangular, handwritten in italic font, simple frame: Boussu a Etterbeecke, fauxbourg de Bruxelles L** 7. juin 1751 №. 17. B.J. Boussu, a Etterbeecke contre Bruxelles Le 11 fevrier 1753. №. 37.

☞ (1753) Printed, embossed typeface, chamfered decorative frame; sole known example: Benoît Joſeph BOUSSU, Maître Luthier à Bruxelles 175𝟯.

☞ (1754–61) Printed, narrow rectangular (10×41 mm), plain frame: BENOÎT-JOSEPH BOUSSU, Me. Luthier à Bruxelles [,] 17__

Inscriptions Boussu typically applied ink directly onto the wood, often on the back plate next to the upper block. He frequently reproduced the full text of his label verbatim, in contrast to many luthiers who would simply sign their last name or date, or use initials for internal inscriptions, reserving full "imprint" for the labels.

Branding Marks Eight of Boussu's instruments, all crafted after 1759, bore a small, 13-mm wide branding mark reading 'BOUSSU' applied with a branding iron just below the button on the back. At least two instances of non-authentic branding have been identified, marked as 'B BOUSSU'/'B.BOUSSU' with misaligned horizontal text.