Recently, evaluating the accessibility of cities and territories to facilities and amenities represent a major challenge to meet the objectives of sustainable urban development. Although issues related to accessibility are epistemologically old, they are regularly undergoing a renewal of their operations through academic approaches as new theoretical concepts and planning models. In particular, the study is about the “15-Minute City” or “city of short distances” (Büttner et al. 2022), which measures the performance of access to amenities on a local scale, with the aim of strengthening active modes such as walking. The diversity of approaches and methods, available in the literature, employed to assess proximity-based accessibility necessitates taking into consideration the effects of urban scales, distances and service types in the evaluation rules. This study presents an innovative methodology to (i) assess the accessibility to reach amenities and services and (ii) identify potential areas for future development of a territory that promote the accessibility by proximity. The first part of the methodology uses a classic approach in the literature to assess and qualify the accessibility of neighbourhoods to the opportunities of a territory with the use of geospatial data and route calculation algorithms. To this end, different types of amenities (education, health, retail, commercial and shopping centres, as well as leisure areas and green spaces) and a number of proximity access distances corresponding to these categories of opportunities, according to different modes of transport, were selected. This approach takes into account the distances, times, urban scales and the types of transport modes with a focus on active ones. The methodology that considers various transport modes such as public transports, the use of private vehicles as well as active modes, with the help of the capabilities of the r5r software (Pereira et al., 2021). As part of this research, the Marne-la-Vallée area located in the eastern region of Paris, France, was chosen to apply the methodology. The study area is a “new city” developed since the 1960s according to a discontinuous linear urban growth of the form of a Transit-Oriented Development (TOD) structure located around the stations of Regional Express Railway line. Since the development planning policies of this territory are founded on accessibility and also since the study area is on newly developed region, it is important to investigate its outcomes in terms of accessibility. This first approach provides a robust measure of overall accessibility, taking into account physical distance, travel times, and ease of access to amenities and services. It is thus possible to develop a typology that qualifies the level of accessibility performance of neighbourhoods to the various amenities. After this first diagnostic phase, the second part of the methodology focuses on identifying areas suitable for future development of the territory on the basis of its urban framework reflecting the accessibility. Using demographic and cartographic data of buildings, amenities, services and reserved areas, as well as transport networks, the different polarities (urban centres) of the study area are organised in the form of an iterative function system, using the Fractalopolis software (Bonin et al., 2020). Based on fractal geometry to construct a multi-scale urban framework, the system identifies locations that may experience increased demand for new infrastructure and amenities in the future (Yamu and Frankhauser, 2015). Taking into account both the current accessibility to different types of amenities, the importance of each pole in the urban organisation of the territory and future growth projections, the methodology offers a global perspective on areas suitable for urban development, particularly services and housing. By combining these two steps, the proposed methodology provides policymakers and urban planners with a multi-scale decision-making tool to assess accessibility and identify the most appropriate areas for the future development of the territory. The information generated by this methodology can thus help promote balanced and sustainable development in urban and regional areas, ensuring that facilities and services are accessible to all residents with a degree of proximity that limits car use and favours active modes. The methodology has the potential for broader applications beyond the specific case study area. By adapting the geospatial and analytical frameworks to different regions and incorporating relevant data, the methodology can be customized to fit diverse contexts. This flexibility enhances its usability and applicability in various urban planning and development scenarios. References : Bonin, O., Bonneau, P., Clerc, M., Cousin, J., Frankhauser, P., de Gouvello, B., Haffner, M., Lehmann, X., Pioli, R., Poirel, M., Stransky, V., & Thébert, M. (2020). Projet SOFT (p. 214 p.) [Research Report]. ThéMA, UMR 6049 ; Institut pour la Transition Energétique, Efficacity ; LVMT. Büttner, B., Seisenberger, S., Baquero Larriva, M., Gante, A., Ramírez, A., & Haxhija, S. (2022). Urban Mobility Next 9 ±15-Minute City : Human-centred planning in action Mobility for more liveable urban spaces EIT Urban Mobility Munich November 2022. Pereira, R. H. M., Saraiva, M., Herszenhut, D., Braga, C. K. V., & Conway, M. W. (2021). r5r : Rapid Realistic Routing on Multimodal Transport Networks with R5 in R. Findings. Yamu, C., & Frankhauser, P. (2015). Spatial accessibility to amenities, natural areas and urban green spaces: using a multiscale, multifractal simulation model for managing urban sprawl. Environment and Planning B: Planning and Design, 42(6), 1054–1078.