Good question, and not one I've been able to get to the bottom of.French Wikipedia
has this to say:
La plupart de ces billets furent remplacés ŕ la suite de l'ordonnance du 4 juin 1945 tandis que les coupures inférieures ŕ 50 francs disparurent.
(Most of these (namely the Vichy issue) banknotes were replaced following the ordinance of 4 June 1945, while denominations lower than 50 francs disappeared.)
This tells us that the Vichy banknotes continued to circulate for up to a year in liberated areas. It would be logical to suppose that the smaller denomination banknotes and the coins also did so, but I can't find incontrovertible evidence.
On the main Wikipedia page about the French franc
, there is more information about what circulated during the occupation/Vichy period. At the start of the period, both Reichskreditkassen coins ("washers") and standard homeland-type Pfennig coins circulated in the occupied zone. Belgian coins apparently circulated in Nord-Pas de Calais, and Alsace-Lorraine officially adopted the Reichsmark. The Reichskreditkassen money was withdrawn in 1941 and standard German currency in 1943, after which Vichy money presumably circulated across France.
In terms of long-term circulation of Vichy coins, it's only really the 1 and 2 francs that are affected. The 10, 20 and 50 centimes were only minted by the postwar state until at the latest 1947, and there were no Vichy coins higher than 2 Fr to continue in use (excluding the Pétain 5 Fr that was never issued). It wouldn't surprise me if the 1 and 2 Fr coins remained technically valid until 1960 but were actually not used because people disposed of them ASAP.
All of the above raises another question though: What did they use for denominations between 5 and 50 francs between 1945 and 1950? As mentioned, Vichy notes of under 50 francs were withdrawn in 1945, but the coins of the relevant denominations were not issued until 1950.