The basic rule is to hyphenate between syllables but there are many other rules that forbids (or at least strongly discourage) some hyphenations and specify where precisely the hyphenation should occur in some cases.
Here one of these rules is preventing the first syllable to be isolated because its ending "x" is followed by a vowel. The last syllable has a mute "e" which would have ruled out hyphenation should it had less than three letters but this isn't the case here.
The only possible hyphenation is then before the last syllable:
Note that there is no full consensus about the rules, this page is stricter and states exemple cannot be hyphenated.