Given a quantized analytic cycle (X, σ) in Y, we give a categorical Lie-theoretic interpretation of a geometric condition, discovered by Shilin Yu, that involves the second formal neighbourhood of X in Y. If this condition (that we call tameness) is satisfied, we prove that the derived Ext algebrais isomorphic to the universal enveloping algebra of the shifted normal bundle N X/Y [−1] endowed with a specific Lie structure, strengthening an earlier result of Cȃldȃraru, Tu, and the first author This approach allows to get some conceptual proofs of many important results in the theory: in the case of the diagonal embedding, we recover former results of Kapranov, Markarian, and Ramadoss about (a) the Lie structure on the shifted tangent bundle T X [−1] (b) the corresponding universal enveloping algebra (c) the calculation of Kapranov's big Chern classes. We also give a new Lie-theoretic proof of Yu's result for the explicit calculation of the quantized cycle class in the tame case: it is the Duflo element of the Lie algebra object N X/Y [−1].