This paper focuses on the monitoring and the analysis of the recent connection between the two largest district heating networks in Geneva, Switzerland. Each network has its own owner, operator and type of supply. Before the connection, one was supplied by gas boilers and the other by the municipal waste incineration combined heat and power (CHP) plant. The connection aims at improving heat recovery from the CHP. In this paper, the overall district heating system is analyzed by a systemic approach where both supply and demand side for thermal energy is studied, as well as its impact on the electrical energy production. Based on actual hourly data, an analysis of the resource availability, heat and power production and load profile is made. An input-output model of the system is developed in order to evaluate the heat recovery potential and elaborate scenarios regarding future district heating extensions and buildings refurbishment. Considering the present heat demand profile and waste availability, heat recovery from the waste incineration plant could increase from 142 to 233 GWhth thanks to the connection. Network extensions could increase it to near 300 GWhth even if a share of the heat demand is reduced by energy saving measures.