I understood that 있는 + noun means 'having the noun mentioned' ,however this sentence is not making sense which I saw in a video: 또한 프랑스에 있는 한국 회사에서 일을 하고 있습니다.
You understood incorrectly. The basic meaning of 있다 is "to exist": other meanings are derived from it.
마당에 [토끼가 있다]. = In the front yard, [a rabbit exists] (i.e., there's a rabbit).
나는 [아파트가 있다]. = As for me, [an apartment exists] = I have an apartment.
회사가 프랑스에 있다. = The company exists in France = The company is (located) in France.
[프랑스에 있는] 회사 = a company [that exists in France] = a company in France
펜이 있는 사람 means 'a man who has a pen' or 'a man with a pen'.
ex) 동생이 있는 사람 / 차가 있는 친구 / 많은 경험이 있는 선생님
있다 has many different meanings and there is no equivalent expression in English for each usage. But anyway its basic meaning is 'exist' or 'have something'.
Here is the link for Naver dictionary lihttps://ko.dict.naver.com/#/entry/koko/7be7a557934e4e9e9426fb407f94de27