Hi Miles and Pat.
My sincere apologies!
I mis-read the information on the 'ET' mark, which was the forerunner to the 'Swan' mark.
The full text taken from 'A Guide to Old French Plate' by Louis Carre is;
"The decree of June 29, 1893, discontinued the use of the 'ET' mark which had been created on January 13, 1864, for marking plate coming from countries without customs conventions, and replaced it by an 'owl' in an oval frame for gold and a 'swan' for silver. This reform had been rendered necessary by the Customs Law of January 11, 1892, which stipulated that all imported gold and silver plate should comply with the same conditions as plate manufactured in France"
"The 'chimera' mark, which was being used for imported watches and clocks, was abolished. All goods of this nature, no matter where they come from, had to bear the 'owl' or 'swan' mark, but any watches or clocks marked with the 'chimera' are still in order"
My apologies again.