Yes - but....... they do have 'flushes' ie times when they produce pounds and then far less whilst they are going into flowering mode ready to produce a big flush for a second time.
I would go for more than one French bean variety oran early one and sow early May, late May and early June (possible until early July in the balmy south of the UK), just to even out the amounts that can be harvested.
On the other hand, you might sow an early variety, which gives you an early harvest and whilst you are away on the summer hols, the beans do their 'go slow' ready for the second big flush in September. This could work out well, it is all a matter of timing and your preference.