This article investigates the incorporation of Portuguese immigrants and their descendants into the janitorial profession in Paris, a role historically filled by migrants. Notably, the profession is characterized by residential requirements—janitors live in the buildings where they work. Today, Portuguese-origin janitors constitute about 75% of the 10,000 concierges in Paris’s private park buildings. Our research is based on 66 in-depth interviews conducted in December 2022, alongside analysis of concierges’ Facebook groups, union publications since the 1930s, interviews with union representatives, owners’ organizations, and statistical data from public agencies. We outline how, since the early 1960s, Portuguese immigrants established dominance in this sector, influenced by housing transformations, economic shifts, labor market demands favoring European immigrants, and strategic economic decisions by Portuguese households. The paths to becoming a concierge are varied, including immigrant women, career changers, Eastern European immigrants post-socialist regimes, and the economic downturn of 2008, as well as students who are children of Portuguese concierges. The article also distinguishes between ethnic and cultural dimensions of being a concierge of Portuguese descent, demonstrating their significant overlap. Finally, we compare the unique integration model of Portuguese janitors with other urban immigrant integration models like ethnic neighborhoods or enclaves, underscoring the creation of an ethnic niche that illustrates the nuanced societal position of Portuguese immigrants and their progeny in France.