The Internet of Things has emerged as a paradigm in a variety of application domains where several parties share data to tackle specific tasks. However, these IoT data can be sensitive and the data subject wish not share them with other competitor organizations without retaining some level of control. Thus, a privacy-preserving, user-centric, and transparent solution is needed to deal with the challenges of IoT data sharing, such as the loss of control over the shared data, the trust need in data consumer infrastructure, and the lack of transparency in terms of data handling. Therefore, we propose PATRIoT, a privacy-preserving PlATfoRm for IoT data sharing using a service-oriented approach. The latter is proposed based on the blockchain technology, which enforces privacy requirement compliance according to the General Data Protection Regulation. For validation purposes, we deploy the proposed solution on a private Ethereum blockchain and give the performance evaluation.