It is widely used in French technical education (Bac STI2D, BTS, CPGE) as a practical guide for "Sciences de l'Ingénieur". Where to Find the Manual
Standard symbols for screws, bearings, gears, and joints. memotech dessin technique pdf
So go ahead. Find that PDF. Print the section on cotation de perçage (hole dimensioning). And next time a young intern asks you what “⌀10 H7” means, you can just slide it across the table and smile. It is widely used in French technical education