On the face of it - there were all the signs of an Entente Cordiale between Boris Johnson and the French President Emmanuel Macron as the pair met in Paris for talks on Brexit - with smiles, handshakes and jokes about Mr Johnson putting his feet up on the Elysee furniture. (Subscribe: https://bit.ly/C4_News_Subscribe) But behind all that bonhomie - a stern line from Mr Macron - who warned the Irish backstop was "indispensable" - telling the PM to set out his alternatives to the mechanism as soon as possible.