Low-cost sensors are considered as a promising tool to contribute to urban air quality policies. In some initiatives, based on citizen sensing, they are used to gather data and gain a better understanding of the problem, thus fitting in a technology-oriented smart city model. In others, closer to citizen science, they are used to engage citizens in finding solutions, therefore fueling a more citizen-oriented smart city model, the smart enough city. Although important, the political effects of such initiatives have not been widely analyzed so far. To address this issue, we have studied Ambassad'Air, a citizen sensing initiative led in Rennes since 2016: What are the political consequences of this project? And which smart city model does it fuel? Based on a littterature review, we built an analytical framework for the two smart city models. Then, we realized 81 interviews with Ambassad'air's volunteers and managers to analyze the initiative's strategy, its implementation (participatory mechanisms; use of data) and its political effects (change in political agenda or projects; citizen mobilization). Initially, micro-sensors were lent to volunteers with the aim of turning them into peer-educators able to raise awareness around them and into empowered citizens able to influence local air quality policies. However, the initiative faced implementation barriers (persistent blurring between citizen science and citizen sensing; limitations to produce problem-oriented, scientifically validated, mass data) that limited its short-term political effects. It has sparked a local interest, though, for micro-sensors, and it is questionning the management of citizen-produced data. With no political mechanisms that transform citizen sensing from a practice to an input for risk regulation, Ambassad'Air is not quite yet a tool of a smart enough city. But as a way to produce sensitive environments that any citizen can interact with in real-time, it is a step towards a more senseable city.