This excerpt taken from the SNY 6-K filed Sep 23, 2005.
D.13.5. Cumulative translation differences
Cumulative translation differences at December 31, 2004 and June 30, 2005 break down as follows:
On first-time adoption of IFRS as of January 1, 2004, all cumulative translation differences for all foreign operations of the Sanofi-Synthélabo group were eliminated through shareholders equity, having been deemed to be zero at the IFRS transition date. Cumulative translation differences previously recorded in the Aventis balance sheet were eliminated as of the date of the acquisition.
The movement in cumulative translation differences during the period was primarily due to the effect of changes in the US dollar exchange rate on intangible assets, goodwill and deferred taxes.