On Vendémiaire 25, year 4 of the Republic, the mathematicians, astronomers and members of the Académie des Sciences Jérôme de Lalande and Sylvestre François Lacroix sanctioned the "most accurate and perfect large-scale map of Paris of its kind ever executed". They were referring to the great 1:1728 topographical map of Paris, designed, surveyed and drawn under the supervision of Edme Verniquet since 1784, which was then in the process of being engraved. A masterpiece of 18th-century mathematical science and surveying techniques, comparable to the Cassini map on a city scale, the “Verniquet map” has been preserved in the form of a printed atlas, supplemented by a considerable number of sketch maps and a manuscript volume documenting the surveying operations for the map's trigonometric canvas. This atlas des opérations trigonométriques is truly a unique insight into the real-life conditions under which mathematical and topometric knowledge was put to the test on the eve of the French Revolution. Leveraged by historian Jeanne Pronteau from a historiographical point of view, the “atlas of trigonometric operations” is a powerful critical tool for a major map in the history of Parisian cartography. An in-depth exploration, in the light of modern surveying techniques, helps us to understand and retrace the strategies used by 18th-century cartographers to detect and compensate for measurement and calculation errors. We also present a renewed "geometric" analysis of Verniquet's map, based on a twofold quantitative assessment. The first is an intrinsic assessment of the uncertainties of general triangulation and ground-level survey operations. The second explores the absolute planimetric accuracy of the positions of a set of elevated points in Paris, from which Verniquet and his cartographers constructed the canvas of their map of the city.