French Tax Seal - Ministere Finances
France - 'Ministere Finances' appears on the French tax seal required on all lighters for use in France.
It was required from 1911 through 1945 and, so, dates any lighter with it to being produced and sold within that time frame. The stamp is bone shaped (think Milkbones!) typically, bit in some circumstances may be round.
The earliest of the tax seals had the year on them and typically the year was 1911 from 1911 - 1916. Around 1927 the stamp was apparently changed with the initials C and I entwined or superimposed over one another on either side of the circle with the two "C"s facing one another (as shown in picture). C I stands for "contibutions indirectes". This can further help to date anything with the seal on it.
At some point along the way, possibly 1926, another more discrete seal comes into play - it is "BL" (effectively, Deluxe Lighter) and is for the higher priced lighters.
Belgium - This wording (Ministere Finances) also appears on the Belgian tax seal, but the Belgian seal has a standing Belgian Lion on it (as pictured). The Belgian tax seal was required beginning in 1923 and extending through the 1930s. Some other countries used both paper stamps and metal seals including Spain, Italy and Argentina.