The origin of guillemets in France
The usage of quotation marks dates back to times before typography but it was only in 1527 when Guillaume defined them for usage in printingWikipedia France. This was mainly done for France.
Interestingly even later in 1663 the German typographer Schottel, being the first who systematically wrote a guide for using punctuation in German typography did not define quotation marks in his "Ausführliche Arbeit Von der Teutschen HaubtSprache":
Original scan from the contents on punctuation from Schottel, 1663
There is quite a concise essay on the development of the French guillemet written by Pedro Uribe Echeverria (L'Express). From this we can see that the guillemet is likely to have originated from simple marks in handwritings:
After that there may have been an evolution using quotation marks similar to those used in English and German:
Guillaume postulated to have these marks
- on the same line as the letters, and
- to have them related to parentheses
Thus the known form (« ») used in France today resulted.
Guillemets in Germany
For Germany there is no rule to invert these "French" guillemets. In fact in the mid 19th Century only the French way of setting them was mentioned:
Carl August Franke: Handbuch der Buchdruckerkunst, 1855
Later - by the end of the 19th Century - both variants were possible:
Anführungszeichen (Gänsefüßchen, frz. guillemets), zwei Paar Strichelchen („-“) oder Häkchen («-» auch »-«), welche dazu dienen, die Gedanken oder Worte jemandes, specielle Bezeichnungen, Buchtitel u. dgl. hervorzuheben.Brockhaus 1894-96
I was unable to find any reference for a rule or a convention that conclusively explains why
later guillemets were inversed in modern German (but not Swiss) typography. Some say that it may be connected to not being able to print guillemets in Fraktur. The most convincing idea however may be that it was merely a simplification of typesetting that led to inversed guillemets:
In Deutschland setzt man Guillemets am liebsten mit einwärts gewandter Spitze. Dies bringt den Vorteil mit sich, daß man den Abstand zwischen dem Guillemet und dem benachbarten Buchstaben nicht händisch zurichten muß. Daneben ist gelegentlich aber auch die Manier mit auswärts gewandten Spitzen anzutreffen. Hier wendet sich die Seite der Glyphe mit der vollen Höhe dem benachbarten Buchstaben zu. Der Setzer darf nicht zulassen, daß sich die Zeichen berühren oder zu nahe kommen. Deshalb bleibt diese Variante Fällen vorbehalten, wo größere Sorgfalt angewandt und damit Geld und Zeit in Kauf genommen werden. Belles Lettres
This together with a preference for other letters than in French (including many upper case letters within sentences) may be the only reason why typographers inverted the guillemets in Germany.