500 Francs Pascal, type 1968, head-to-tail watermark

The 500 Francs Pascal had one of the longest production runs of any modern French note — nearly two decades out of the Chamalières facility, which the Banque de France had operated since 1923 specifically to maintain inhouse control over security printing. The "head-to-tail" designation in the watermark classification distinguishes this type from the earlier single-orientation watermark issues; a minor technical refinement, but one that collectors use to separate the series into distinct subgroups.

Fontanarosa's design, rendered in intaglio by Armanelli and Durrens, honored Blaise Pascal — mathematician, physicist, religious philosopher — an unusual choice for a circulation note, given that French banknote portraiture had long favored artists and statesmen over scientists. Pascal had been lobbied for inclusion since at least the 1950s.