Can I get a student discount?
At current there are no discounts for international student card holders. So if you have a university student card from Australia for example then it will not be valid to use on European trains. However, most rail operators do apply age-related fares for certain routes. By entering your date of birth in your passenger profile you will be able to benefit from these fares when they are available.
The only discounts given for European trains are through rail cards. This means a rail card must be purchased to have any discount applied. SNCF sells various age related cards such as the Cart Jeune 18 - 27. So if you are travelling for a while by train in France, this card could be a good option. Though remember, discount cards cannot be used for international journeys.