"Via Alsace" stamp
Between 1872 and 1874 (the last known date), letters to Switzerland were sometimes stamped VIA ALSACE.
A brief analysis of these letters shows that:
- they generally come from the northern half of France or from northern countries for which France provided postal transit to Switzerland;
- they were all insufficiently franked or not franked at all;
- that they entered Switzerland via BASEL.
Letter from LILLE to DAGMARSELLEN (Switzerland) with insufficient postage at 25 c.
The rate for Switzerland had been 30c since 1 October 1865. The Franco-Swiss postal convention of 22 March 1865 stipulated that in the case of a letter with insufficient franking, The tax to be charged to the addressee was the difference between the postage for a postage due letter (50 c) and the amount of the stamps affixed to the letter. However, if the tax was a fraction of a decimal, it had to be rounded up to the next decimal. So here we have:
- tax on the letter without postage: 50 c
- postage due: 25 c
- tax payable 50 c - 25 c = 25 c rounded up to 30 c.
The Franco-Swiss postal agreement of 1865 provided for 2 main outgoing points for French dispatches to Switzerland: ST LOUIS and PONTARLIER.
However, from 1871 onwards, a new player began to interfere in Franco-Swiss postal relations: Germany.
Since the annexation of the French eastern departments by Germany, France could still send mail to Switzerland via PONTARLIER. However, it also needed to be able to keep a more direct and more frequently serviced route for mail from the northern half of France.
So on 15 February 1872, the route to BASEL was reopened, but via BELFORT (instead of ST LOUIS) and annexed Alsace (Monthly Bulletin no. 35, February 1872).
This passage through Alsace increased the cost of transport and the transit duties to be paid to Germany. We do not have the figures for France, but in 1872, for example, Switzerland had to pay 11700 Fr more than in 1871 for transit fees via Alsace (report of the Federal Council of 1872, page 163). In 1873, Switzerland still paid Germany, 20700 Fr in transit fees (Federal Council report 1873, page 37).
Swiss or French stamp?
The primary sources available to us do not explain this, but the VIA ALSACE stamp was above all a Swiss accounting mark, probably applied in BASEL, intended to identify the route taken and thus remunerate the right country (in this case Germany). France had no interest in identifying the route taken by its dispatches in the France-Switzerland direction. It might have had an interest in doing so in the other direction, but this stamp is never found on Swiss letters to France.
For letters with insufficient or no postage, Switzerland needed to be able to identify the route taken. Switzerland had to pay part of the tax either to France if it passed through PONTARLIER or to Germany if it passed through Alsace.
We do not know when this postmark was introduced either, but we can assume that it appeared with the application of the Franco-German postal convention of February 1872 (applicable from 22 May 1872). The Swiss Federal Council's report for 1872 (page 139) listed "Introduction of the exchange of direct dispatches with France, via Alsace, in application of the agreement between Germany and France" as one of the year's main decisions concerning the Post Office.
The first known letters date from December 1872.
The last known letter, posted in COMPIEGNE, dates from 23 September 1875.
The end of this postmark is also poorly documented, but we can assume that it took place when France joined the General Postal Union on 1 January 1876, Switzerland and Germany having already joined on 1 July 1875. Inter-country transit duties were probably revised.
This postmark is probably very uncommon, as it was only used on mail with insufficient or no franking. At the time, the vast majority of mail to Switzerland was postage paid. Moreover, it only concerns one route into Switzerland, from BELFORT to BASEL.