I have been wondering about that ever since I first saw this photo. My initial reaction was the same as yours. However, as you probably know, Merckx licensed out his name to several bicycle manufacturers, the two most famous being Falcon in England and Miyata in Japan. Some of those models were relatively inexpensive entry level models and not the type of bicycle you would expect to wear the Eddy Merckx marque.

Merckx in business, was apparently like Merckx on a bicycle.- ruthless. He wanted to conquer every market and widely licensed his name, some would say indiscriminately for the highest dollar. After all, pro cycling careers have a relatively short lifespan and the really big money didn't arrive until the mid-1980s, when Greg Lemond ushered in changes.

In Fance, Eddy licensed him name to a company called Star Nord. If you look at the subject folding bicycle, you'll see a French Fabrication sticker on the top of the seat tube and the fork blade has remnants of a chevron decal in the French tri-color with a star at the top. The latter is the Star Nord emblem and it was prominently displayed on the bicycles that Star Nord marketed under the Eddy Merckx brand (see attached photo). So, this opens the possibility of a legitimately licensed Merckx model. As noted previously, the Merckx name was allowed to appear on some pretty low end Falcon manufactured models and this would have depended on the terms of the contract. If Star Nord offered enough money, they may have had open license to brand any type and level of bicycle, without further approval from Merckx.

So, there is enough circumstantial evidence to support it being legitimate, though I can't make a definitive statement as I have never seen a Star Nord catalogue with this particular bicycle. Maybe the OP has come across one? Perhaps, an appropriate topic for future threads by the OP would be to cover each of the Merckx licensees?

Edit: Sorry for derailing the thread, but the set-up by the OP's title was irresistible. Hmm, does that make me a derailleur?