To use Code Compare with Git Extensions, you need to add the following lines to the gitconfig file:

[difftool "codecompare"]
cmd = \"C:\\Program Files\\Devart\\Code Compare\\CodeCompare.exe\" -W \"$LOCAL\" \"$REMOTE\"
renames = true

[diff]
tool = codecompare
guitool = codecompare
[mergetool "codecompare"]
cmd = \"C:\\Program Files\\Devart\\Code Compare\\CodeMerge.exe\" -MF \"$LOCAL\" -TF \"$REMOTE\" -BF \"$BASE\" -RF \"$MERGED\"
trustExitCode = true

[mergetool]
keepBackup = false

[merge]
tool = codecompare
guitool = codecompare

Note: The global gitconfig file is located in C:\Users\MyLogin\.gitconfig. The config file for a local repository is located in repository root in the ".git" folder (this folder is hidden by default).