A revolutionary design used twice
The design dates from 1792: Augustin Dupré created it for the coins of the newborn First Republic. It came back in 1848, when the Second Republic chose it for its gold 20 francs, made in 1848 and 1849 only. The next regime brought in the imperial portrait, that of the Napoleon III 20 francs.
From 1871, right after the fall of the Empire, the Third Republic went back to the Genius. It produced plenty in the 1870s, stopped all striking from 1880 to 1885, then made few until 1894: that lean period is what left the rare dates. From 1895, the Mint returned to several million coins a year. Bound by the standards of the Latin Monetary Union, the Genius remained everyday money until the 1914 war.
Chaplain's 20 francs Rooster replaced it in 1899. Dupré's design lived on, though, on the large gold coins: the 50 francs until 1904, the 100 francs until 1914. The page on Third Republic coins (in French) sets the coin among its contemporaries.
Privy marks, burnished flans and fakes to watch
Only one mint struck the Genius, Paris; any letter other than A under the wreath is a warning sign. The recognised varieties concern the privy marks, small reverse symbols belonging to the chief engraver and to the Mint director. Two years have two of them: 1879, with a plain or barred anchor, and 1896, with a fasces or a torch, which Le Franc numbers separately. Set apart, the burnished flans of 1848, 1878 (30 coins) and 1889 (100 coins) were presentation pieces.
The rarer a date, the more it tempts forgers. An 1888 or an 1892 therefore deserves a look at the last digit under a loupe: shape, alignment, the surface of the nearby field, tool scratches. A common coin with a re-engraved date still holds its gold, but it is no rare date.
Other fakes copy the whole coin, sometimes in gold of the right fineness. Be wary of wings with blurred feathers, a thick rooster, badly spaced edge letters or a weight that strays from 6.45 g. At 21 mm across with a crisp edge, the coin passes the first test; the next steps are explained in the guide to spotting a fake coin (in French).
Judging the grade of a Genius
On this small coin, the low-relief scene wears in a very readable way. The head, shoulder and chest of the Genius, the highest points, fade first. The wings follow, their feathers losing their outlines. The rooster and the rods of the fasces come after.
Feathers still separate and a sharply cut profile: the coin is Very Fine (TTB in French grading). Wings reduced to a flat area and a rooster without detail: it drops to Fine (TB). On the other side, watch the veins of the wreath leaves, a good witness of wear. The legends around the rim, on the contrary, hold up for a long time and do little to help.
Even with little circulation, a Genius often bears small knocks in the fields, left by contact with other coins, and the grade takes them into account. Above all, no cleaning: the original lustre never comes back. The grading guide and the page on why not to clean a coin (both in French) cover these points.