Holidays in France

Official national public holidays. Regional and religious observances may vary by area.

About Time in France

Midnight Became Ten Hours, and Almost Nobody Adjusted

On 24 November 1793, in the radical push to decimalise everything from currency to the calendar, the National Convention decreed that the day, from midnight to midnight, would be divided into ten hours, each hour into a hundred decimal minutes, and each minute into a hundred decimal seconds. Midnight became zero hours, or equivalently ten; noon fell at five hours exactly. The mathematics were genuinely elegant, since a day that was seventy percent complete could be stated as simply the end of the seventh hour rather than sixteen hours and forty-eight minutes, and clockmakers duly produced dual-faced clocks showing both systems at once. The idea itself long predated the Revolution, having been floated by the mathematician Jean le Rond d'Alembert as early as 1754, but ordinary people had no practical reason to relearn how to read a clock, and every household's existing timepiece would have needed replacing at real expense. The requirement was made optional again on 7 April 1795, not eighteen months after it began, though a handful of towns kept using decimal clocks into the early 1800s before the country reverted fully to conventional timekeeping on 1 January 1806.

The idea did not die completely. In 1897 the Bureau des Longitudes, with the mathematician and physicist Henri Poincaré serving as secretary, floated a compromise: keep the familiar twenty-four hour day, but divide each hour into a hundred decimal minutes and each of those into a hundred decimal seconds, avoiding the need to relabel the hours themselves. Even this milder proposal failed to gain any public traction and was formally dropped in 1900, and no French government has attempted to touch the base of the clock since.

A Law That Refused to Say the Word Greenwich

When the International Meridian Conference in Washington fixed the Greenwich meridian as the world's zero of longitude in October 1884, the French delegation was the leading holdout, having used its own reference line through the Paris Observatory since 1667. Railways forced a partial retreat first: in 1891, to simplify timetables, the whole of metropolitan France adopted Paris mean solar time, about 9 minutes and 21 seconds ahead of Greenwich, with train companies themselves running five minutes further behind even that, apparently as a small courtesy to less punctual travellers.

Full alignment with Greenwich came only on 9 March 1911, twenty-seven years after the Washington conference, and even then the law preserved a measure of national pride: rather than naming Greenwich outright, it defined French legal time as mean Paris time, retarded by nine minutes and twenty-one seconds, arriving at the identical result through a formula that kept the Paris Observatory, not an English one, as the nominal point of reference. France stayed on this Greenwich-equivalent time, with a one-hour summer variant from 1916, until the German occupation shifted the country to Central European Time in 1940, an offset that, unlike the wartime changes in several neighbouring countries, was never reversed after the war.

A Tower, a War, and a Time Signal That Never Stopped

From 23 May 1910, the Paris Observatory used the Eiffel Tower, fitted with an underground radio centre near its south pillar since 1909, as an antenna to broadcast hourly time signals across France, out to ships at sea, and eventually to its colonies, marking one of the earliest uses of wireless telegraphy to spread civil time rather than merely to send messages. On 20 November 1913 the observatory used the same tower to exchange signals with the United States Naval Observatory in Arlington, Virginia, a transmission designed specifically to measure, by wireless rather than by ship-borne chronometer, the exact difference in longitude between Paris and Washington.

The following year, astronomer Benjamin Baillaud, acting on a report by the engineer Gustave Ferrié, organised an international conference in Paris that in 1912 established the Bureau International de l'Heure, a body charged with combining time signals from observatories worldwide into a single, agreed Universal Time, seated at the Paris Observatory itself. Statutes were not formally ratified before the First World War intervened, but the bureau operated in practice regardless, and Baillaud kept the Eiffel Tower's time signal broadcasting throughout the war years even though the German long-range gun known as Big Bertha was, according to the tower's own historical record, aimed at the nominal geographic coordinates of the Paris Observatory. The bureau's work continued under the International Astronomical Union after 1919 and was only wound up in 1987, when its responsibilities passed to the International Bureau of Weights and Measures, headquartered a few kilometres away in Sèvres, which computes the world's Coordinated Universal Time to this day, keeping the global reckoning of time anchored, however informally, to the Paris region where it was first coordinated internationally three-quarters of a century earlier.

Two Rival Clockmakers and a Race Britain Almost Won Alone

The popular history of the longitude problem centres on the Yorkshire carpenter John Harrison, but France was pursuing the same goal on a nearly identical timetable, and briefly ahead of it: the French Academy of Sciences, funded by a bequest from Rouillé de Meslay, had begun offering prizes for improved navigation in 1714, narrowly before the British Parliament's own Longitude Act of the same year. Serious French work on marine timekeepers did not intensify until mid-century, when two Parisian clockmakers, Pierre Le Roy and Ferdinand Berthoud, became open rivals in the field.

Le Roy completed a sea clock in 1766 incorporating a detent escapement, a temperature-compensated balance and an isochronous spring, elements that historians of horology consider foundational to the modern chronometer regardless of Harrison's earlier practical success, and the Academy awarded him its Meslay prize in 1769. Berthoud travelled twice to London hoping to learn Harrison's methods directly, was twice refused a demonstration, and instead pieced together details secondhand from the English watchmaker Thomas Mudge before building his own instruments; he was never able to match Le Roy's results in sea trials, but he built far more of them, going on to become clockmaker to the French navy and later to Louis XV, and claiming more than fifty timekeepers sent on some eighty voyages over his career. Their public dispute over who truly deserved credit for the underlying invention ran for years in pamphlets and Academy reports, a distinctly French postscript to a race popular memory has mostly told from the English side of the Channel.

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