From Saumur there's a 6 km long secundary road (back road) called Rue du Boumois and it leads to a little chateau. It looked quiet and empty but with plenty of parking space, indicating it must be quite well visited.
As it happened, we were there at the wrong time, it was closed during the lunch break.
Architecturally it is interesting as it shows the change from gothic to early renaissance.
The link below can be translated into English, using the google link at the bottom left.
Overall, a visit takes an hour, English, German and French is spoken.
Opening times and admission fees are all mentioned on the webpage.
We came across this funny sign in German. It reads:
Vorsicht, freilaufende Hunde ausser Besichtingungsperiode.
Wann Hunde kommen, flach auf den Boden legen und auf Hilfe warten. Viel Gluck
That means: outside opening hours there are dogs on the loose. When dogs come, lie flat on the ground and wait for help. Good luck!
That must be a joke. And if not, you know what to do!
Which reminds me... this wasn't in Saumur. It was just outside Saumur on the north river bank of the Loire at a small chateau. I'll look up the name...