The Lavender Hill Mob (1951)

Alec Guinness stars as a mild-mannered transporter of gold bullion who has spent 20 years moving gold bars to banks in an armored truck. Then one day he simply decides to help himself to a million British pounds' worth of the gold, but to pull off the heist he enlists an old friend who sculpts and manufactures paperweights. Once the gold is hijacked, it's molded into souvenir miniatures of the Eiffel Tower and shipped off to Paris. Panic ensues when six of the gold miniatures are mistakenly sold to a group of English school girls.