A preservative cannot be used in Europe unless listed in the positive list published as the Annex V of the Regulation N° 1223/2009, which was enforced in lieu of the former Directive on July 11, 2013.

See the full list of the preservatives authorized in Europe
• in the paper: "Preservatives" in the How to choose your cosmetics section

Also see the papers dealing with some preservatives
• Parabens
• Phenoxyethanol
• Triclosan
• Formaldehyde releasers