Directly - probably not, what are your output choices? If you have the Step option you can input an assembly.
Some iges translators also accept assembly format.
Step is a translator, you can output solids & assemblies.
There are different options in step, check for the options coming out of inventor. You will want to keep the file in assembly format.
AP214 is also a much better format than AP203, (both are STEP variants) as it will retain more of your original information. Information pertaining to things like layers, part names, and whatnot.
Thank you DBezaire and Solid7, I have had a result and was thanked by out customer for reeciving the model, I save the inventor file as a STEP and it imported into Catia with no problems. Cheers