Here in Germany, customs have the right to disregard what is declared on the label, and they like to make use of that right. In that case you don't receive your parcel but only a letter that asks you to come to the customs office and assist them in opening the parcel and finding out the actual value (show an invoice, printout of ebay auction, credit card bill, etc).
Luckily the customs office is only 2km from where I live (less lucky people have to drive 50km), and one of the officers is a quite nice girl
To determine duty fee, they need to know the exact type of item: watch, non-precious metal, electrically operated, opto-electronic display.
If you like bureaucracy, try the "Browse" button
here
E.g. for a digital non-precious-metal watch, TARIC code is 9102120000 -> duty is 4.5%, min 0.30EUR, max 0.80EUR.
In addition, you always have to pay 16% (soon 19%) "Einfuhrumsatzsteuer" (nice word, isn't it

= import turnover tax), not only on the item value, but also on the shipping fees!
These are the rules - I try not to get upset when I have to pay.