Tunisia is located on the north coast of Africa almost south, across the Mediterranean, of the northern part of Italy. It was part of the Ottoman (Turkish) Empire but became bankrupt as a result of its high seas piracy. It was taken over as a French protectorate in 1881. Your coin is from the French era. 'Bon pour 2 francs' means 'good for 2 francs.' The 50 centimes, 1 franc and 2 franc coins look the same except, of course, for the 'bon pour' part. These coins are made of aluminum bronze.
The coin catalogs quote fairly low values for these coins, unless you happen to find one of the few made out of silver. Here are the catalog values. These values are approximately correct for all dates.
worn: less than $1 US dollar catalog value
average circulated (like our picture): $2
well preserved: $3
fully uncirculated: $10
50 centimes dated 1345/1926 are less common and catalog at $25 when fully uncirculated
50 centimes dated 1352/1933 are slightly scarce and catalog at $50 when fully uncirculated
average circulated (like our picture): $6
well preserved: $15
minted in silver: $200 in average circulated condition
worn: $4 US dollars catalog value
average circulated (like our picture): $12
well preserved: $35
minted in silver: $500 in average circulated condition
Use our Important Terminology page to convert these catalog values to actual buy and sell values.