An apostille is a certificate delivered by an authority in the country of origin of the document (Secretary of State in the US, passport office in Australia). The Apostille is attached to your original document to verify it is legitimate and authentic so it will be accepted in one of the other countries who are members of the Hague Apostille Convention.
France requires apostilles on all birth certificates (and other documents) from Australia and North America as well as many other countries outside the European Union.
For countries such as Canada, who are not members of the Convention, there is a similar system called legalisation.
Translations required for certain calls for tender and administrative procedures may require legalisation by a Chamber of Commerce, the ministry of foreign affairs, etc. This process is carried out by the translator.
Click on the country for more information on apostilles or legalisation in Australia, New Zealand, the United States, Canada, South Africa and the United Kingdom. You can look after the apostille or legalisation yourself or go through a company. There are many on the Internet.
The Australian Embassy in Paris can issue apostilles for Australian documents.
Theoretically, as they are international documents, they do not require translation but some French authorities insist. If you need an apostille from the US, ask for a multilingual version. They are easily available.