The result is higher than the average of 528 million euros expected by analysts surveyed by Factset.
The group attributed the rise in part to "the implementation of plans to boost and make more flexible its businesses in the current context of low crude oil prices."
Last autumn, Repsol announced it would lay off 1,500 people worldwide by 2018, out of a total of 25,000 employees.
The group said it had saved "more than 500 million euros" in the first quarter of the year, and aims to economise 2.1 billion euros for the whole of 2017.
"The partial recovery of international raw materials price indices" also helped raise profits, with net income in its upstream exploration and production unit reaching 224 million euros, compared to just 17 million euros in the first quarter last year.
Energy producers across the world have reaped the benefits of oil prices that have been on the rise following actions by the OPEC oil producers' cartel.