In this article a research work in the field of content-based image retrieval in large database applied to the Paleontolgy image database of the université de Bourgogne, Dijon, France called "TRANS'TYFIPAL" is proposed. Our indexing method is based on multiresolution decomposition of database images using wavelets. For each kind of paleontology images we try to find a characteristic image representing it. This model image is computed using a classification algorithm on the space of parameters extracted from the wavelet transform of each image. Then a search tree is built to offer users a graphic interface for retrieving images. So that users have to navigate through this tree to find an image similar that of to their request. Our contribution in the field is the building of the model and of the search tree to make user access easier and faster. This paper ends with a conclusion on first coming results and a description of future work to be done to enhance our indexing and retrieval method.