This report deals with the content of the planning schemes. Its aim is to assess the flexibilities in their content, in their application and to know how they can produce effects. It was a hard work because the concept of a flexible plan is ambiguous (there is no definition). Nevertheless, some key learnings have been identified: There are dedicated instruments for flexible planning in almost all countries. The way flexibility is carried out can be found either in the content of programs and plans (known for their elasticity/plasticity) or in the legal relationships between plans (the hierarchy or articulation between them). Technically, four categories of flexible plans can be identified: • The socalled strategic or ‘programmatic’ or ‘spatial planning’, whose main purpose is to orientate urban planning by setting major objectives, options or directives. Most of them are ‘schemes’ covering a mainly large spatial scale. In principle, they are not binding on builders’ projects; • Strict plans with flexible zones or reserves of flexibility (regulatory plans or allocation plans); they are spatially or territorially restricted (to cities in particular) and more adapted to rule land use concerning parcels. They are binding on builders’ projects; • Totally flexible plans; these plans do not in themselves create obligations for their addressees, but are nevertheless intended to produce effects; • The UK’s plans. In the UK planning system, the plan is not fundamental and is not a legal document in the sense given in most other European countries. The plan is one of many assessment elements for the granting of permissions. Beyond plans, the UK’s whole planning system is inherently and explicitly flexible. A general trend is emerging: in all countries, the elements of flexibility are growing. This is a consequence of the sophistication of the rule of law, of democracy and of greater respect for fundamental freedoms, as all actors must act with care for others. Therefore, studying flexible plans consists in studying the methods (analysing how the various instruments of planning law allow the rules to be adapted to concrete situations and changing circumstances) and the political and institutional system of each country as well. Finally, this report is a reflection on what the law is and on the means to compel in a democratic society: how can different actors be led to act in a certain direction without explicitly or systematically strict legal constraints?