First sign your are buying fake Diesel Jeans/clothing,
they do not use the red and black tags anymore, for a little over a year now.
New tags should be cream with very close matching white lettering that says Diesel with the info on a white sticker on the tag.

Also a huge sign that your looking at fake Diesel jeans is the black and white label that gets stapled on the back with the size like how they used to in the 90's, say like Levi's or other jeans like so


nothing new should have that tag on the back.

it should look more like this


Also study your style your buying.
The huge ones I always laugh at are "NEW MENS X-ROTUCK 796"
9 times out of 10 this jean is going to be fake. This model has not been made for years and the chance of someone finding a new pair is slim to none. If your going to buy this model, you're better off buying it used with actual wear markes in it so you know it was real.

There are alot of misspellings/problems I always see in listings too
" NEW WEMONS ZATHAN SIZE 26"
the zathan model is a male model.

just research the jean your about to bid on.

look for the tags. this is a huge sign of fake sellers from asia/middle-east