Your 10 franc coin with the 'Millenium of King Capet and France' commemorative design is very modern. These coins were made in platinum, gold, silver, and non-precious metal.
worn: less than $1 US dollar approximate catalog value
average circulated: $1
well preserved: $3
fully uncirculated: $7
Values for precious metal issues depend on the base value (BV) of the coin. Find BV by multiplying the current value of precious metal (see, for instance, kitco.com) by the precious metal content of the coin.
SILVER (contains 0.347 troy ounces silver):
fully uncirculated: BV + $10
GOLD (contains 0.355 troy ounces gold):
fully uncirculated: BV + $40
PLATINUM (contains 0.450 troy ounces platinum):
fully uncirculated: BV + $60
The nickel-brass issue weighs 10 grams and the gold issue weighs 12 grams, so if you are not sure of the difference between nickel-brass and gold, a jeweler's scale will reveal content. Similarly, the silver issue weighs 12 grams and the platinum issue weighs 14 grams.
The gold issue contains 0.3549 tr oz, and the platinum issue contains 0.4496 troy ounces of precious metal.
Be sure to look up the current relevant precious metal value - they change every day.