I think your search is so difficult because you are looking at a very basic tenet of freethinkers which may not be possible to pin down. Note that back then the authority of the masters or kings was claimed to derive from gods, so the exclamation is somewhat redundant. I've seen some German early socialist/anarchist texts where "no masters no gods" or so is the underlying message.
Below I'm translating a snippet about artist Andre Breton. Let me know if you run into German that needs translating. I tried a google.de (German) search for "Weder Gott noch Herr"
Martin Voelker
In the years after the war [Andre] Berton's sympathy for Anarchism becomes more visible. In 'Arcane 17' (1947) he tells of the strong sentiment that had been evoked when, as a child, he had discovered a simple inscription on a tomb stone: "Neither God nor Master".
In der Nachkriegszeit wird die Sympathie Bretons für den Anarchismus deutlicher. In Arcane 17 (1947) erzählt er von dem starken Gefühl, das er als Kind empfunden hat, als er im Friedhof auf einem Grabstein diese einfache Inschrift entdeckte: "Weder Gott noch Herr".
http://www.vsp-vernetzt.de/soz/021124.htm
Ni dieu ni maitre
Theresa A. Tobin
In Guerlac, Othon. Les Citation Francaises: Recueil de passages celebres, phrases familieres, mots historiques avec l'indication exacte de al source suivi d'un. Paris: Librarie Armand Colin, 7th edition, 1961, p.286 only Blanqui is cited as the source. "Ni Dieu ni maitre. Devise d'Auguste Blanqui, agitateur communiste (1805-1881, qui en fit le titre d'un journal lance en vovembre 1880."
answer
hey,
"ni dieu. Ni maitre" is a pretty old french slogan, already used in the 18th century in occasions such as the revolution in paris. Anarchism was 'created' by Bakounine (reffered to as the father creator of anarchism) in the early 19th century, and it became their slogan, especialy after the publishing of the book Ni Dieu, Ni Maitre and the newspaper of the same name.
Since, its been used by many for other circumstances. It still is the anarchist slogan [and a very popular tattoo for them], and there actually was something after it at the beginnings but i cant remember it right now..
But anyway, its been used by many in France to protest and by freethinkers. In May 68, against the pope, religion in general, against the president today (Sarkozy), or many other demonstrations ( feminist, or other more common issues)
so right now its hard to find things about its actual origins, as its been so distorted and overused, but its origin is french political philosophy mainly ( Bakounine), and Blanqui's book.
you might get to know more about it on anarachist websites, in Bakounine's texts to understand it or in Blanqui's or other anarchist books.
Its also quite known as 'Ni Dieu, Ni maitre, Ni Ordre Moral!'
hope that helped you.
If i remember the following of the one actually used by the anarchist ill send it.
Tammy