Les économies urbaines subsahariennes et le problème de la mobilisation de ressources via le secteur informel.

Based on the recent studies of the local economies in Western Africa and on survey data about the informal sector of Bobo-Dioulasso city (Burkina Faso), this work aimed to contribute to the reflection on the mobilisation of the fiscal resources in the average cities for financing city development. It confirms the marginality of local budgets in regard to the rawlocal product and the communal expenditure which increased with the decentralisation. Thismarginality of local budgets is mainly the consequence of the ineffectiveness of the fiscal administrations in the informal sector. Actually the informal sector is very heterogeneous anddifficult to encircle compared to the modern one. But, it's possible to overcome this difficultyas proved by typological analyses of the informal sector – realised by means of the method ofhierarchical classification coupled with an analysis of multiple correspondences – because inthis sector there are homogeneous subgroups for which an adequate policy of support or a fiscalone can be applied. Built for this occasion, the optimisation model gives a theoretical esquireto the problems of the taxability of micro-units. This model allows to analyse these problemsand to propose strategies of taxation of the informal units going in the direction of an adaptedfiscal policy. This model deserves to be completed and improved, by introducing for examplemechanisms of instigation, penalty or deterrence to enrich the analysis. (Full text in French)