PDF to Photoshop recover layers

Your file won't open with Illustrator; it worked for me with version 10.

A PDF made in Photoshop will reopen in Photoshop with its layers (if it hasn't been flattened).

In Illustrator, it's like a "layer cake" of paths and images. You can delete the images and keep the paths; the opposite is useless because it's the paths that determine the surfaces in the image (clipping mask), and thus the images are regular geometric surfaces. Switch the display to outline mode to get a better understanding.

Once you have the paths in Illustrator and delete the images, you can fill them with whichever surface color you want (provided they are closed surfaces, of course), and you'll have a beautiful map in vector objects....

Pepito One, could you tell me the procedure to follow?
Thank you very much in advance, even if it doesn't work!

In Illustrator, a PDF file created in Photoshop will open in pixelation with recovery of traces if it was not flattened before exporting to PDF.

Similarly, in Photoshop, the PDF file will open with layer recovery if it was saved from Photoshop without being flattened and with the option to preserve the editability of vector data.

If the document has been flattened, there is nothing left to recover except a simple image...

I opened it with Illustrator, and when I hover over my document (it's a map of a town), it highlights the different elements. This means it hasn't been flattened? In that case, how do I open it in Photoshop to retrieve the layers? Do I need to save the file in a certain way with Illustrator?
Thanks in advance.