Slecmann -v- Deutches Patent und Markenamt 
European Court of Justice C273/00 (2002) 

EC law provides that a trade mark may consist of any sign capable of being graphically represented particularly words including personal names designs letters numerals shapes of goods or their packaging provided that such signs are capable of distinguishing the goods and services of one undertaking from those of other undertakings (EC 89/104)
The Court’s decision was that a smell (defined as balsamically fruity with a slight hint of cinnamon) could not be registered as a trademark whether as a chemical formulae, a description in words or by depositing a sample.
For background information on trade mark law see