How should I repair this old map?

[oldpewter]

Don't use Scotch tape! If you REALLY NEED to repair the tears try using bookbinders conservation tape. It is ph-neutral and can be removed wiothout leaving a residue on the paper. Always place the repair tape on the rear of the item. The tape is available from serious bookbinding craft shops and available as paper or plastic tape. The tapes are manufactured in the USA.

[Dean]

Thank you OP, I appreciate the advise! \
~Dean

[Nige H]

My advise would be to leave well alone, keep the map stored “as is” in the case. If you really feel the need to get this restored then get it done professionally, as paper has to be one of the most tricky things to try and invisibly mend and so its not a project to undertake without experience, also the damage or should I say folds in the paper will still remain if the map is restored and then refolded again to be put back in the case! So why go to the trouble and expense.

Nige.

[sebfrench76]

Taking the map out of it's case will expose it to the sun UV's and may turn the original colors into something quite pale...(that's my idea...don't know about the quality of the german inks)