A study for one of La Tour's most celebrated early self-portraits called either La Tour à l'index or La Tour à la croisée'. The portrait was exhibited at the Salon of 1737 and its name derives from the fact that it shows La Tour laughing, leaning on a window and pointing with his index to the left. A number of versions of that portrait exist (A. Besnard, op. cit., nos. 212-228) of which many are not authograph.
Albert Besnard dated the pastel to the later period of the artist, though it is clearly connected to the Salon portrait: his expression is identical, frowning and showing his teeth through his open mouth. The hat sketched in the drawing is clearly the same as the one in the final composition.
La Tour executed another similar sketch of himself, formerly in the Goncourt collection and now in the Louvre, E. Launay, Les frêres Goncourt collectionneurs de dessins, Paris, 1991, no. 170. In the Louvre sheet La Tour also chose to limit himself to the physiognomy, eliminating all secondary details such as the ears or the hair that would alter the purity of the expression, leaving a large portion of the sheet untouched. The Louvre pastel dates from the same period as the present one, though La Tour depicted himself with a different look, more jaded, as the Goncourt brothers observed.
Further self-portraits drawn in the same economical way are illustrated in A. Besnard, op. cit., nos. 246, 252, 247-8, figs. 7-9, 259. This type of drawing, of which La Tour drew a number, he used as preparatory studies, probably drawn quickly in front of the sitter and later used in the studio for finished productions.