France produced 37,072,000 1/2 Franc coins in 1974. Switzerland produced 45,006,000 (plus another 2,400 in Proof) 1/2 Franc coins in 1974.
That was a standard circulation issue that's readily available even though France adopted the euro in 2002. The franc was worth 12 to 14 U.S. cents so your coin has a face value of 6 or 7 cents.
since France franc is using euros, it goes for 10 to 15 cent euro.fa
I just got a 1910 one half Swiss franc in a pile of foreign coins.
Australia has never used the Franc as a unit of currency.
This was a common circulation coin until France switched to euros in 2002. At that time your coin was worth about 8¢
The value of a half franc in pounds depends on the specific exchange rate at the time of conversion. You would need to look up the current exchange rate between the currency of the franc and pounds to get an accurate conversion.
You need to be more specific. First, what country are we talking about? Many countries have (or had) currencies known as the Franc. Secondly, if this is a coin, you need to provide the year and an estimate of condition (for example, a 1843 French 1 Franc coin that is well-worn).
Silicon
Golden Half ended in 1974.
If the coin is a US Kennedy half dollar dated 1974 it has no silver in it and is face value.
There was no British 1974 Half-Sovereign minted. The first decimal British Half-Sovereign was minted in 1980.