Wikipedia is right, Russian
Ж is a retroflex fricative (IPA: ʐ), and the sound sample they have in the article is exactly how it sounds in Russian.
If you pronounce it like the Portuguese and French "j" (IPA: ʒ), you will be understood well, but this will add a foreign accent to your speech, I'd advise sticking to the correct, retroflex fricative variant. Russian
Ж (IPA: ʐ) can never be "soft" (palatalized), even when in spelling it is followed by the palatalizing vowels (е, ё, и, ю, я,), so
жизнь is actually pronounced as
Жюль Верн as
*Жуль Верн, etc.
In Russian there is another phoneme, a long (gemminated) voiced palato-alveolar fricative (IPA: ʑː which can also be transcribed as ʒ:), which is normally spelled
ЖЖ, like in
вожжи, дрожжи, жжение, жужжать, можжевельник. But this sound is now substituted in the speech of most people by /ʐ:/, that is it loses its palatal nature, the tendency in Russian is to have all Ж-like phonemes non-palatalized.