ex-(french president) was what they were trying to say, but unfortunately that doesn't look good as a headline. french ex-president doesn't sound right to me,

ex-(french president) was what they were trying to say, but unfortunately that doesn't look good as a headline. french ex-president doesn't sound right to me, because that would mean a french person who is an "ex-president". Subtle difference, but to make a point let me stretch it out a bit. He could be an "ex-president" of anything, maybe an ex-president of a high school class, and just happens to be a french guy. What they're trying to say is a person who is an "ex-president of france", so the "ex" prefix applies to "french president".