"simplest French period"

Hello, teachers.
I am puzzled over the word order of the following phrase:

in a very charming little room furnished after the style of the simplest French period

I guess "French period" refers to a period when England was ruled by the Normans, but why is this word modified by "simplest"? I could easily understand this phrase if the latter half went like 'after the simple style of the French period". Could you tell me the meaning of "simplest" in this instance?

I'm not a teacher, but since the sentence is talking about furniture, I would understand it this way:

"The room had furniture which was similar to that produced in the least ornate, least decorative, or plainest French period."

I would say that here "simple" means "not ornate", "not fancy", "not decorative", "plain".

I see.
Thank you, stuartnz, for your quick reply.