In the project Print Your City!, urban dwellers transform their plastic waste into raw material for public space, creating a circular stream within the city. This is achieved by recycling household plastic waste with robotic-3d-printing and producing components that upgrade the built environment through citizen involvement and the principles of circular economy. The city provides a suitable field for large, long-lasting and easy to reprocess applications for recycled plastic. At the same time, the technology of robotic-3d-printing enables a short recycling path and a zero waste production process that can combine modular repair and mass customisation; and can maximise the use and value of the material resources. Furthermore, involving citizens in the material collection and the design process increases recycling rates and results in customizable parts that fit the needs of the neighbouring area. This circular city strategy boosts the local economy by locally sourcing materials and locally producing goods. The built environment develops sustainably by accommodating the demand for plastic from local resources, and simultaneously solves municipal disposal problems and involves citizens in the production process of public space.