It looks like that it should be very easy to find a software that can convert CATIA technical drawings and parts (.catpart) and export them to IGES format (.igs, .iges). The most obvious choice would be of course some of the Dassault Systemenes CAD programs (including CATIA), but you may also find some 3rd party programs that support CATIA formats.
Open CATPART file Open IGES fileA CAD viewer program with conversion capabilities
A set of 3D modeling tools
3D CAD/CAM tool for product development
A CAD converter with huge format support
A CAD visualizaton, analyzation and translating system
A 3D CAD translation software
A dedicated CAD converter