This document analyses a feasible way to accommodate interoperability elements for the data component of a spatial data infrastructure (SDI) and extend the meta model framework for interoperability (MFI) in securing interoperability among heterogeneous domain information models under the smart city context. This document: a) outlines the interoperability issues for city domain information models; b) reviews relevant standards and best practices and examines methodologies or solutions to tackle the interoperability issues; c) supposes a use case and provides an example to secure interoperability among different domain information models using model registry; d) specifies technical requirements in concern about how to apply the interoperability elements of the meta model framework to support the interoperability of smart city services; e) highlights the standardization items to be developed to secure interoperability.