Abstract: For similarity based searching, multimedia data are represented by one or more numerical vectors: we search the nearest neighbors of the query. Because of the huge number of these data and their high dimension, classical indexing technics are inefficient. The goal of this internship is to study the use of euclidean lattices for database indexing. Lattices have nice properties: they are spatial quantizers, thereby generate a partition of the space and decoding (quantization step) may be done very quickly. Then, we hope to be able to rapidly find a small space region containing data similar to a given query point, without reading all the database.