Fedora builds of the gtk3 version of Inkscape from the upstream inkscape trunk. The current stable release of Inkscape is version 0.48. This repo periodically publishes in-development versions of what will become inkscape 0.49, but with the optional compiler flag that enables gtk3 support turned on. Additionally, this build of inkscape also enables the gtk3 dark theme by default, and uses the GNOME symbolic icons by default also.
download the repo file for your version of Fedora to the /etc/yum.repos.d/ directory with a command like:
sudo curl -o /etc/yum.repos.d/ryanlerch-inkscape-unstable-gtk3.repo \ http://copr.fedoraproject.org/coprs/ryanlerch/inkscape-unstable-gtk3/repo/fedora-20-i386/
then update inkscape with
sudo yum update inkscape
The following unofficial repositories are provided as-is by owner of this project. Contact the owner directly for bugs or issues (IE: not bugzilla).