Is one who found a woman's wristwatch in a prayer area on a travel route sinful if he took it after searching for its owner and not finding him, and is there a way to announce it?

If a traveler finds a lost item, he must not take it with him. Rather, he must announce it for a full lunar year in the place where it was found. If it is impossible to return it to its place for announcement, he should give it as charity on behalf of its owner, and it should be spent on all acts of righteousness and closeness [to Allah].