is it legal  

Go where the money is
In case it might be legal,(i personnaly think it is as an independant distributor) what would be your selling proposition that other web sellers do not offer to customers? By selling design items you would have to be honest saying what is an original vintage and what is a copycat, or a a la manière de... or in style of...
eBay can give you a pretty good exemple of" what to sell attitude". On the internet village you can get in touch with most world collectors who are not afraid spending 4000 euros for a real vintage gerald Summers chair or 2000 euros for a standard Prouvé chair. Considering your offer, make sure you would meet customer's needs first, (the design demand for middle class is just emerging) before spending money on a retail shop waiting for hypothetical clients. One reasonable answer would be to elaborate a Business Plan first. My personnal opinion, forget about European demand,don't mess around here and go start a design retail business in DUBAI.( a place in the global village that gathers overwealthy investors).

It is always legal...
to buy copies, They are not drugs or other prohibited substances. You can always sell them legally as long as you do not pretend they are originals or that, because of lack of information, the consumer could have the impression that it is an original. Let's face it there is no moral issue here. Intellectual property laws were never based on moral considerations. They are based on commercial and economical considerations and when the protected time period is over it is over. That's how this kind legislation was developed and how it is written. In a democracy we do not only respect the law but also the spirit of the law. All the rest is a balancing act between commercial interests, the selfish and grasping desire for possession we call greed, and snobism.
Let's not be fooled, if Cassina, Knoll or any of the others that pretend having rights on the basis that they throw some money toward the money-hungry estates of some of our great architects and designers, had a real "design" agenda, they would use their experience and market recognition to promote and produce young design talent and let "vintage" be real vintage....did I open another Pandora box?
If I wanted to do this in my beloved Belgium, I would take a completely different angle. Belgium is known, not necessary as the birthplace of comics but at least as the largest producer of comics in the world. Considering that most of these "classics" in furniture have been featured in interiors shown in the comic pages, I would start a retail store with good reproductions of the classics but refering to them as..."the chair in the interior of this or that vilain or hero" It would take some research but...

...enlargements
of the strip would give a good "Pop-art" backdrop to any of these displayed classics...but watch it, the copyrights on comic strips last much much longer than the intellectual property on furniture..

BACKGROUND POPART simply brilliant M. KOEN
Beyond business, a smart association of design and visual communication could be a nice concept. Some contemporary artists did well on popart communication . We could just imagine Mies van der rohe copies in front of a Roy Lichtenstein poster on the wall. Both of them would be for sell.
http://www.lichtensteinfoundation.org/frames.htm

thank you
thanks Koen. Your philosophy is in line with mine. Are you a lawyer ?

Lau & Frank
Yes.Mr.Vaeres
Guess who am i ?
Seems we will still get some really useful informations from here

Hi.Frank
Just to hide ur name,not mean to spell mistake.
🙂

How do you call....
Re"....Seems we will still get some really useful informations from here..."
How do you call these fishes again who swim in and out the open mouth of the hippopotami and live off the residue between his teeth?

hi lau, hi koen
living off the residue between the hippopotami's teeth is not like living in the best conditions, I don't really understand what you mean by this. In fact, who's the hippopotami in these matters?

I guess that's...
what you call an inside joke...sorry to abuse public space. I should not have done this...

Hi Frank
I think he is laughing at me,he means deal with replicas always are a little business that Knollstudio and Cassina pay less attention on those little profit.and some replica is legal because 25 years have passed til the design in public.
Also he compare those replicas as the residua of the hippo teeth slot.maybe compared with the huge budy of the hippo,it is not nutritious at all.
But I think sometimes I will be able to provide same nutrient residua as the normal feedings.

Hi Frank
Hi,Frank,
How is your business now? now I am most concerning about the ball chairs,swan & egg etc.
I am wondering if I can get some vintage information for the replica improvements.