lib/texinputs/isabellesym.sty

 \newcommand{\isasymordmasculine}{\isatext{\rm\textordmasculine}}
 \newcommand{\isasymsection}{\isatext{\rm\S}}
 \newcommand{\isasymparagraph}{\isatext{\rm\P}}
 \newcommand{\isasymexclamdown}{\isatext{\rm\textexclamdown}}
 \newcommand{\isasymquestiondown}{\isatext{\rm\textquestiondown}}
-\newcommand{\isasymeuro}{\isatext{\textgreek{\euro}}}  %requires greek babel
+\newcommand{\isasymeuro}{\isatext{\euro}}  %requires eurosym
 \newcommand{\isasympounds}{\isamath{\pounds}}
 \newcommand{\isasymyen}{\isatext{\yen}}  %requires amssymb
 \newcommand{\isasymcent}{\isatext{\textcent}}  %requires textcomp
 \newcommand{\isasymcurrency}{\isatext{\textcurrency}} %requires textcomp
 \newcommand{\isasymdegree}{\isatext{\rm\textdegree}}  %requires textcomp