A slight correction: the Portuguese pronunciation of Alexandre is [əlɨ'ʃɐ̃ⁿdɾɨ] and the Brazilian pronunciation is [ale'ʃɐ̃ⁿdɾi]. Alexandra is [əlɨ'ʃɐ̃ⁿdɾə] in Portuguese and [ale'ʃɐ̃ⁿdɾə] in Brazilian Portuguese.
The pronunciation in French is more like a-lek-XAWNDRe, it's an x, not an s. That's why my friend prefers to be called Alex because otherwise people say his name wrong.
Alexandra is [əlɨ'ʃɐ̃ⁿdɾə] in Portuguese and [ale'ʃɐ̃ⁿdɾə] in Brazilian Portuguese.