The only similarities between the Chanel bag and that RM bag are the chain and flap style. That's it. Flaps with a chain are a very popular styles and can be found with all the brands.
I personally love flap style bags, have many Chanel flaps and just got a Miss Dior flap which is veeeeeeery similar to Chanel.
Chanel flaps have always had a major influence on the bag industry because of the iconic position. So Chanel influenced the development of that flap bag with a chain segment. It's not the matter of inspiration anymore, it's an established style of bags already.
Good point!