Gun Before Butter is the 3rd book in the Nicholas Freeling Inspector Van der Valk mystery series. This book was published in 1963. Freeling died in 2003 at the age of 76.
from the back of the book:
Called by the Observer "the best and deepest of Freeling's books," this investigation of a seeminly senseless murder in Amsterdam not only sends Inspector Van der Valk to France, but involves him emotionally as well.
This story is character-driven without a lot of action. The writing is concise. The ending surprised me. There's a mention of Maigret early on, which I found amusing. There's a mention of the movie Marie Walewska and the book Gone with the Wind. There's one passing mention of a fencer: "He stayed still a second, clearing his mind, preparing it, like a fencer before the start of a fresh bout." An undiscovered painting by Breitner is an important element of the plot. There is a picture of a painting by this artist at the top of the post.