Context in “stateless” component?

What you have provided under your definition of “Stateless:” function is not what a Stateless function is. You have provided your action creator as a thunk. I assume you wanted to insert the code for your Client component instead. To access context in a stateless component, your Client component would do something like this (which is documented here)

const Client = (props, context) => {   
    return  <div >{context.localizedString("someKey", "someFallback")} </div>
}

Client.contextTypes = {
    localizedString: React.PropTypes.func
}

export default Client