Could someone confirm my assumption about Btwin Original 520 Hybrid front wheel? My friend has a Btwin Original 520 Hybrid Size M (Specs)
His bike's front wheel was stolen and I would like to replace it with something cheap (no need for the dynamo hub, for example).
I am a little confused with all the available wheel sizes and models and worried that I could buy something that won't fit.
The rear tires (factory ones) are marked 700x35c, but the specs say that 26'' is the right size for the Medium Size. 

From the specs: 


  WHEELS: Single-wall, machined, anodised aluminium rims. 
  SHIMANO front hub dynamo. The quick-release system makes it easy to remove the wheels when transporting your bike.
  
  TYRES: Versatile, highly durable road/path B'Twin tyres. Dimensions: size M 26 x 1.75. Size L 700 x 1.75
  Tyres with reflective strips offer excellent lateral visibility at night.


Also, when it comes to wheels I am guessing by the specs that I should buy 1.75'' width.
When I search for rims on amazon I am faced with all sorts of different sizing standards (32H, 36H, 700, 26'' etc). Could someone please indicate whether 26'' x 1.75'' inches are the right way to go? Can I then put 700x35c tires on it?
Are there equivalent sizes using another standard (like 36H) that are equivalent (in cae I am looking for them on amazon)?  

Thanks in advance.
Your friend's bike will have the same size wheel on the front and back. If the rear wheel is 700c then the front wheel will be that size. The imperial equivalent of 700c would be 28 inches.

Finally, I'd suggest going to Decathlon or use their website and buying a replacement wheel with a dynamo. The price difference is minimal (less than a set of lights would cost).