The title of the window "Mise en page de la table du pilote" (equivalent of Formatting Pivot Tables, I guess) in French should be "Mise en page de la table de pilote", with "de" and not "du".
Also, the generated page is named "Tables du pilote_base_1" which should be "Table de pilote_base_1" in correct French
Please upgrade to 5.2.3 at least (it is a good practice to always test the latest version of any software before reporting bugs to its developers). That was an obsolete translation that has been updated in newer versions. The new French name for this feature is “table dynamique”; in 5.2.x the string in question is translated to “Mise en page de la table dynamique”. As there are no more releases upcoming for the 5.1.x series, this is not going to be fixed there.