She and her husband Jacques van Marken [nl] were involved in the manufacture of yeast throughout their lives, and were engaged in the co-operative movement, taking care of their workers.

Matthes and Van Marken created living quarters for workers in her hometown, Delft in South Holland, named Agnetapark after her.

[2] Matthes' sister Sara Elizabeth,[2] who was affectionately known as Nora, married Zionist politician Arnold Kerdijk (1846–1907), the founder of the Free-thinking Democratic League, in 1876.

[2] On 7 October 1869 the couple married just before the first yeast factory in the Netherlands, the Nederlandsche Gist & Spiritusfabriek NV, opened.

[2] When Matthes learnt that their marriage would be childless, she decided to dedicate her life to her husband's business and career, and participated in the establishment and management operation.

Matthes and van Marken maintained close contact with the employees of the factory and their families, which appealed to the couple's sense of community; they wanted to be part "of a larger whole".

[5] Van Marken and Matthes took care of the three surviving children, Cornelis, Clara, both adolescents, and Anna, a young child.

[4] Jacob Cornelis Eringaard, the eldest illegitimate son of van Marken, later headed the Gist & Spiritusfabriek and pursued the social interests of his father and his wife.

[6] The daughter of Jacob Cornelis, Erry Anna Eringaard, was married in 1932 to the diplomat and publisher Daniel Johannes von Balluseck (1895–1976).

Also because of this, extensive records of the business ventures and career of Jacques van Marken exist, while only a few sources mention the activities of Matthes.

She undertook an empirical analysis of the housing needs of 48 working families, equipped Agnetapark significantly, and was influential at least during the early years in the management of her husband's other companies, especially in matters of personnel.

[7] Matthes and van Marken, who was called a welfare engineer by his contemporaries,[9] developed a premium wage system for his factory workers of the Nederlandsche Gist & Spiritusfabriek NV (1869), under which all employees could receive bonuses of two to 20 percent of their salary in addition to their basic salary "for good work and because of zeal".

[10] Due to van Marken's health problems, François Gerard Waller, his nephew, was entrusted with the management of the factory in 1886.

[10] In 1873, Agneta Matthes founded her own business, the Delft perfume factory, Maison Neuve, where her husband acted pro forma as owner because of the legal issues.

She participated in international exhibitions, where her perfume brand, PMN (Parfumerie Maison Neuve), won several prizes and gained recognition for her company.

At the height of their success in 1885, when they employed approximately 1,250 employees, their companies were collectively known as, the Delftsche Nijverheid (Delft Industry).

Matthes and van Marken established a corporation for the development of the settlement, and gave the park to its workers in 1870 as a co-operative, in order to prevent speculation.

In response, Matthes founded the Vereeniging voor Armenzorg (Association to care for the poor), helping regardless of religious or political beliefs.

Two critical articles were entitled, "Een levensleugen" (A Delusion of a Life)[23] and imputed ulterior motives of van Marken's undoubted social engagements.

[23] Despite the disappointments regarding Agnetapark, it was an important model for the co-operative development and construction of garden cities for workers.

The park is considered the first social housing scheme which cared about providing hygienic living conditions in a green environment for a high quality of life.