  We give an introductory survey on the universal Vassiliev invariant called
the perturbative series expansion of the Chern-Simons theory of links in
euclidean space, and on its relation with the Kontsevich integral. We also
prove an original geometric property of the anomaly of Bott, Taubes,
Altschuler, Freidel and D. Thurston, that allowed Poirier to prove that the
Chern-Simons series and the Kontsevich integral coincide up to degree 6.
