I am probably not the best person for this since we LOVE nature study. Yesterday it was voted favorite subject of school and today we clambered around a creek bed and walking trail for an hour and a half. Also, realize that kids need outdoor time even if we hate it. It is good for their lungs, their muscles, their eyes, their energy levels, and their emotions. Having said that...
Ways to make it real without a lot of stress (or tons of outdoor time):
1. Create a nature study box of outdoor things like rocks, feathers, bones, dead bugs, etc that you find as you are out and about. Use those as your nature study subjects.
2. I take the camera and take pictures of the plants - trees, grasses, flowers, etc and insects, birds, and animals that we see and use those to make our journals indoors. That way we can see something on the way to the doctor and get a picture - and still count it as nature study. Especially if you are looking up names and identifying them.
3. Get some really good DVDs of insects, plants, animals, water creatures and have your son watch those. Narrate it, draw it, whatever. The real-life photography in these kinds of movies are amazing and bring you into the world from the comfort of the couch.
4. Get kits like ant farms. worm farm, or tadpole thing and take care of it.
5. Get pets that you can observe
6. Go to the pet stores, petting zoos, animal shelters, the zoo, etc. Take pictures and use those to record things in your nature journals.
7. Plant a few flowers in a pot on your windowsill or front step.
8. Hand a bird feeder by a window.
9. Utilize the internet. Identify things that are common in your area and research those in depth - pictures, sounds, locations. See if you can locate some in a specific spot and go see them. Then put it in your journals.
10. Can your husband work on the actual time outside if you do any of the above??
11. Maybe you have a friend who would trade something in exchange for some outdoor time. (I do realize you are in an apartment in France and that may not be an option...)
12. Can he join the Scouts in a few years? That will get him some outdoor time (w/out you, lol)
13. Read lots of books about things outdoors. That helps for when they are outdoors.