French luxury goods maker Hermès posted a 20 percent rise in first-half operating income in line with expectations, helped by strong tourist demand in Japan, the United States and Europe.

The brand known for its silk scarves and Birkin bags costing several thousand euros reiterated on Friday that its operating margin for the full year would be lower than in 2014 due to currency fluctuations.

Hermès' first-half operating margin of 32.5 percent was close to the level of 32.6 percent reached a year earlier. The margin was 31.5 percent for 2014, down from 32.4 percent in 2013.

As expected, Hermès kept its medium-term goal of increasing annual sales at constant exchange rates by 8 percent.

Half-year results from other luxury companies such as LVMH and Gucci owner Kering published last month have been stronger than expected, driven in part by Asian shoppers in big European cities, as well as in Japan and Korea, who helped make up for lower sales from luxury hotspot Hong Kong.

"We remain convinced that Hermes is the most defensive name in the luxury space: a long waiting list and a deliberate effort to 'starve demand' and maintain a 'rarity effect' make it so that Hermes growth and margin performance is more stable than peers," Exane BNP Paribas analyst Luca Solca said.

Hermès shares are up 9.2 percent so far this year after gaining nearly 12 percent in 2014.