As the saying goes, 'imitation is the sincerest form of flattery' - so, Diesel should be very flattered.  Consumers should be aware that unauthorized manufacturers often counterfeit popular and expensive brands.  This doesn't mean that you shouldn't buy online and pass up a good deal, but instead that you should research before purchasing.  The following guidelines are a starting point for your research but are by no means meant to be an exhaustive list.  Additional information can be found by searching "fake diesel" via any search engine.

What to look for in Diesel jeans:

Fabric Quality

• Authentic Diesel jeans use a thin, quality denim that has a somewhat smooth elastic feel while fake Diesel jeans often use a thicker denim of less quality.
  

Micro-Stitching

• Below the 'Made in Italy' marking, there is silvery white stitching that when you look closely will say 'Diesel'.
  
• Older authentic Diesel jeans do not have this stitching, it only occurs on newer models.
  

Small Numbers

• Tiny, hard to read numbers appear above the Indian head tag inside authentic jeans
  

Distress and rip marks

• Authentic Diesel jeans are hand-distressed while fakes are typically created by machine.  Due to this, fake jeans distress marks may appear less-realistic and more like scratches or precise rips.

What to check for on eBay:

* Does the seller include exact photos of the jeans or standard catalog photos; if catalog photos are provided, make sure to ask the seller for exact photos
* It has been reported that authentic Diesel jeans never come in poly bags
* There is a similar brand name called 'Diesel Australia', not to be confused with Diesel
* Always check seller feedback to see if buyers have noted concerns over the jeans authenticity

Note: It's likely that some eBay sellers were deceived when purchasing Diesel jeans for resale and are unaware of how to spot fakes.

Fakes Keep Advancing:

As more people discover how to spot fakes, the counterfeit operations continue to advance their methods in order to deceive the public.

Foolproof Validation:

In order to truly verify if a pair of jeans are fake or not, the foolproof way is to know what an original looks like.  Given that Diesel jeans are expensive, you should study up on what to look for if buying them online.  Visit a local store selling Diesel jeans and inspect them as noted above so you will know what to ask of sellers.  Any reputable online seller will be more than happy to answer your questions.