Counterfeit goods that are in the European Union purely because they are in transit between non-EU countries cannot be seized by customs authorities, according to a ruling of the European Court of Justice. The goods can only be seized if there are grounds to suspect that they will be sold in the EU. The ECJ said that customs authorities must destroy counterfeit goods if the court or other authority believes based on evidence that the goods will be sold in the EU. The evidence could include sale of goods to a customer based in the EU or an offer or advert addressed to people in the EU, or some other documents showing this.
The ruling can be found here: http://curia.europa.eu/juris/document/document.jsf?text=&docid=115783&pageIndex=0&doclang=EN&mode=req&dir=&occ=first&part=1&cid=6211.