Ventilation emerged as an efficient technique to reduce the health impact of dust and gas in workspaces around 1900. However, this technical solution to a major sanitary problem collided with the human factor. When, in 1894, French law imposed shop-floor clearance during lunch to facilitate aeration, workers resisted the injunction as a disturbance of their daily eating routine. Authorities relied on labour inspectors to find solutions to contentious situations. The 1901 union-led strike in the high-fashion district in Paris propelled the issue to national attention. Striking women demanded the strict enforcement of the aeration rule. The executive obliged, but the newfound zeal subsequently rekindled antagonism towards the regulation. Reversing their claim, women workers launched a community-based petitioning campaign to return to pre-strike tolerance. Rumours of another walk-out by seamstresses, triggered by the enforcement of the regulation in 1902, precipitated a governmental volte-face. Authorities apprehended the power of the street and the threat of public disorder. Government yielded to the women's influence. A more relaxed version of the decree – it did not automatically require the evacuation of workspaces – appeared on 29 November 1904. It had taken ten years, and a zigzagging trajectory, to overcome the unanticipated consequences of purposive legislative action. The new rules proved to be very solid: they remained in place until Covid-19 pushed the government to temporarily authorize eating at one's workplace to prevent the spread of the virus in canteens and restaurants.