I had to convert the meters to feet so I could visualize the size better. My sewing room is 10'x10' so roughly 3x3 meters.
I have an L shaped desk in one corner but pulled out about a 1.5 feet from the longer wall in front of the window so we can store things behind the desk (like my old computers that I need to dispose of properly and our space heaters that we use in the winter for example). They can't be seen as they're shorter than the desk.
On a third wall I have two cabinet/bookshelf combos. Bottom part are cabinets and top are bookshelves where I keep all of my sewing, quilting, dyeing and other fiber art books, machine manuals, Cartamodello pattern magazines and many of my PDF/copy shop patterns that have been put into large envelopes. Against this cabinet I have two small part organizers with all of my buttons. Something like this:
tiny parts storage bin In a corner next to the desk is my dress form. On the fourth wall I have a built in closet with a metal bakers rack which is full of large bins of fabric. There are some overflow bins that are stored underneath parts of the desk. When I bought this house I removed the closet doors in both smaller bedrooms and put up curtain rods and curtains so I could maximize the space. They were folding doors and would have required too much space when opened. My ironing board is in front of the closet.
I also have a couple of three drawer plastic containers. I keep one on the desk and it houses thread and such. There is overflow thread in one of the cabinets.
I cut things out on the kitchen counter which is quite large and I can fit up to four of the 34'x24' olfa mats. I was on a multi year sewing hiatus when I bought this house but when I saw the counter I immediately thought it would be a fantastic cutting space. It was actually a major selling point. If I didn't have that counter I would still be able to cut out on my sewing desk although it would be a hassle because the machines would need to be removed and also the lower height would annoy my back.
I find the organizer drawers quite useful and while mine is full of my rather large button collection I can see it being useful for organizing needle packs by size/type, overflow bobbins, etc. You can get them with larger drawers for larger notions. A lot of my notions are all in plastic bins in the cabinets and it's not easy to find what I'm looking for.
All of the stuff in the room doesn't leave much space in the middle of the room left. I have an office chair and then there's a bit of space from the desk to the door. Probably what doesn't work is that I have overflow fabric on top of the desk and the room feels very cluttered.
I think the most important thing is to have plenty of small storage bins for all the small bits and organized in a way that you can easily find things. That is currently missing for me. Just writing this is making me rethink how I store those items.
I'd take photos but the room is such a disaster I would be too embarrassed to post them.