Unusual "1/2 centime en plus" cancel 1896

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This Nov. 7, 1896 cancelled newspaper wrapper from France (not mine) has an unusual hand stamp/cancel/surcharge "1/2 centime en plus" wondering if anyone has seen it before?  Maybe it was revalued....or maybe it's not a wrapper at all, especially as there is no addressee.  Very puzzling!  

Here's a close-up view: