Creating novel ways of sharing data to boost the digital economy has been one of the growing priorities of the European Union. In order to realise a set of data-sharing modalities, the European Union funds several projects that aim to put in place Common Data Spaces. These infrastructures are set to be a catalyser for the data economy. However, many hurdles face their implementation. Legal compliance is still one of the major ambiguities of European Common Data Spaces and many initiatives intend to proactively integrate legal compliance schemes in the architecture of sectoral Data Spaces. The various initiatives must navigate a complex web of cross-cutting legal frameworks, including contract law, data protection, intellectual property, protection of trade secrets, competition law, European sovereignty, and cybersecurity obligations. As the conceptualisation of Data Spaces evolves and shows signs of differentiation from one sector to another, it is important to showcase the legal repercussions of the options of centralisation and decentralisation that can be observed in different Data Spaces. This paper will thus delve into their legal requirements and attempt to sketch out a stepping stone for understanding legal governance in data spaces.