Internet of Things (IoT) has become popular by its characteristics of embedded processing power and network capabilities into a wide range of everyday devices. It is well known that IoT devices are deployed with different characteristics for communication, data format, semantics. Context-awareness gives semantic meaning to IoT devices data by creating a high-level description of the entities situation, called context information. Unfortunately, many context-aware platforms only provide context information for itself and do not care in sharing it with whom may be interested. However, taking into account the heterogeneity of IoT environments, it is necessary to share the context information between different application domains to provide semantic interoperability. This paper presents ConShar, an edge-based context sharing model for IoT environments able to provide context interoperability. We also present related work in the area to clarify the novelty of the proposed architecture and a validation of ConShar‘s context Classification method.