Over the past three decades, urban gardening initiatives have proliferated in cities. The community garden has emerged as a global model for participatory urban greening. To date, few studies have engaged on greening licenses. These schemes have emerged in French cities along community gardens to green the interstices of urban space, such as the feet of trees or holes in pavements. The role of urban gardening in reducing urban environmental injustice is debated in the literature. The cities of Lille and Lyon (France) were selected for study to investigate the geographical distribution of participatory greening initiatives according to the socio-economic profile of neighbourhoods. By comparing the location of community gardens and greening licenses, the role of institutional and associative frameworks in making these schemes accessible to the population was highlighted. A mixed methodology combining statistical and cartographic analysis with qualitative fieldwork was employed. The findings suggest an uneven distribution of greening initiatives in the two cities. The concentration of greening licenses in neighbourhoods with higher average incomes than those hosting community gardens highlights the barriers to participation faced by the most disadvantaged sections of the population. However, the concentration of community gardens managed by charities in these neighbourhoods emphasises the fact that one of the conditions for environmental justice is to support initiatives in working-class neighbourhoods with specific policies. Our results provide useful insights for policymakers on the types of support that should be implemented to ensure that participatory greening initiatives benefit as many people as possible and do not perpetuate urban social and environmental injustice.