Each column is separated into blocks.

Example:

• Column 1: block of 3 letters, 3 letters, 3 letters 3 letters
• Column 2: 1 3 1 7
• Column 3: 3 3 3 3
• Column 4: 1 3 1 3 4
• Column 5: 3 3 3 3
• Column 6: 1 3 1 3 4
• Column 7: 3 3 3 3
• Column 8: 1 3 3 3 2
• Column 9: 3 3 3 3

What do I test?

• Ceasar
• Cipher
• Scythale
• Vigenere... without success

What do we know?

• It's easy to find the solution...

This is a cryptogram from a FRENCH book, "l'imposible affaire des diamants voles."

• If you do a frequency analysis, you will find that the letters conform more or less to a typical French text. This probably isn't a substitution cipher (where letters are encoded), but a transposition cipher (where letters change their positions). Given that the text is made up of tiles, I can imagine that you have to rearrange them, perhaps making a pretty design with the dark tiles. Bonne chance ... Commented Jan 24, 2019 at 20:56
• I will go that way, thanks a lot Commented Jan 24, 2019 at 21:09
• How do you know that it is easy to find the solution? The puzzle is from a puzzle book with a treasure-hunt story. Is there any context that could be meaningful, perhaps a 12x9 tapestry that indicates how the dark tiles should be arranged? Are there any suspicious names, perhaps with K and Z, that could serve as hints here? I have a feeling that the puzzle cannot be solved easily on its own. Commented Jan 29, 2019 at 7:17
• Des illustrations des pièces de la maison abandonnée qui, à l’image de véritables « scènes de crime », recèlent de précieux indices. The book you mention is part of a treasure hunt were you can win 10 actual diamonds, so I'm not sure whether this question violates our "no questions from ongoing competitions" rule. The hunt is over when all 10 prizes have been claimed. According to the web page, four people have won as of 6 Dec 2018. Commented Jan 29, 2019 at 9:37

Apologies first: I do not know French. This is not a solution, just a possible approach.

What we know:

1. The letters are divided into vertical bits.
2. There are dark- and light- coloured bits.

My approach would be:

1. cut the bits according to the dark borders
2. try to rearrange it so that the rectangular shape of the letters are kept.
3. Preferably the dark bits will form a symbol/ pattern when assembled.
4. read from left to right, then from top to bottom.

I am at my wits' end, and hope this may help anyone trying to solve this...

• Thanks i will test, no worry if you are not french, thanks for the help :) Commented Jan 28, 2019 at 11:55
• Nothing interesting :( Commented Jan 28, 2019 at 14:33