In this paper we perform a blow-up and quantization analysis of the fractional Liouville equation in dimension 1. More precisely, given a sequence u k : R → R of solutions to (−∆)with K k bounded in L ∞ and e u k bounded in L 1 uniformly with respect to k, we show that up to extracting a subsequence u k can blow-up at (at most) finitely many points B = {a 1 , . . . , a N } and either (i)N j=1 α j δ a j with α j ≥ π for every j. This result, resting on the geometric interpretation and analysis of (1) provided in a recent collaboration of the authors with T. Rivière and on a classical work of Blank about immersions of the disk into the plane, is a fractional counterpart of the celebrated works of Brézis-Merle and Li-Shafrir on the 2-dimensional Liouville equation, but providing sharp quantization estimates (α j = π and α j ≥ π) which are not known in dimension 2 under the weak assumption that (K k ) be bounded in L ∞ and is allowed to change sign.