In 1997, David Belle's brother Jean-François invited the group to perform for the public in a firefighter show in Paris. For the performance, the group named themselves "Yamakasi", from the Congolese Lingala "ya makási", meaning strong in one's person, or "strong man, strong spirit". Sébastien Foucan also invented a name for what they were doing: ""l'art du déplacement" (French for "the art of movement"). The firefighter performance caused both positive and negative attention. Some members of the group were concerned how the public would view their discipline since the performance did not demonstrate all aspects of it, such as their hard training and their values and ethics. Jean-François also sent pictures and video of the group to a French TV programme, and the popularity of parkour began to increase. A series of television programmes in various countries subsequently featured video footage of the group, and they began to get more requests for performances. During this time, conflicting interests arose within the group. Sébastien Foucan wanted to teach more rather than to train more, and David Belle had the ambition to become an actor. David and Sébastien chose to leave the group, and used the name "parkour" to describe their activity (see § Etymology above). The seven remaining Yamakasi members continued to use the term "l'art du déplacement" (see § Derivative terminologies and disciplines below).