In-laws always seat me away from my child at dining table

No, YANBU. But nobody else is going to sort this for you and the situation isn’t going to change. So either you tell your husband that he needs to ensure you’re sat next to your child, or you get over your discomfort with making things awkward (because this is what they’re relying on) and speak up. Your upset could very easily have been avoided if you had said “it’s my son’s birthday, I’d like to sit next to him”.

I wouldn't call it a microaggression, but it's odd and unnecessary. I'd take your DH at his word and just start asserting your right to sit where you damn well please. Your child is young and still needs his mother. Obviously you want to be seated near him on his birthday. It's understandable that some of the other family want to spend time with him when they can, but that doesn't mean you should be seated far away. Time at the table isn't their only chance to interact with him.

She's not at a distance! She's right there at the table.
The drama is ridiculous..... y'all are acting as if they put her in the garden and locked the door.

What rot.

OP said there were language and cultural barriers - they’re French. Different culture. Why would you jump to racial differences?

Why on earth would you tolerate that.
How genuinely bizarre.
You pick your child up and you sit beside him.
You use your words.

I used to be an au pair in France. Children were expected to sit at the dining table and learn how to eat and appreciate food and drink and talk and participate from an early age. Many French people still take food and the communal dining experience seriously. Perhaps they are trying to give him a taste of that and immerse him in their culture? Perhaps, like many children, he behaves better when there are people he doesn't know so well around him. I would try to regard this as a positive thing. An ability to speak French and to behave in a civilised fashion at table is a great grounding for any child.

Balls to her husband then! Letting the whole family celebrate with him and his son, making a fuss over them and not even including the OP in the photos, while OP gets to watch from a distance like she doesn't even matter to them, which she clearly doesn't

Sooo this 😂😂

If your husband is next to him, what is the issue?

Definitely ask to swap but make sure you are interacting with everyone and not just pandering to your child (this doesn’t go down well in France)

on his birthday you definitely should have been next to him op

Perhaps your mil is trying to give you a break and make his father supervise the meal!

let them deal with your dc
enjoy your meal in peace

I really couldn’t hold my tongue and I’d be saying I’m sitting here, (next to my baby) no discussion.
I wouldn’t be rude unless they were but I’d be adamant!

To be honest this would have been nice for me, enjoying some time without looking after anybody! I used to find it a bit annoying that I was always dealing with the children while their dad was just eating and chatting. But not on his birthday, I would have wanted to sit next to him for that.

I have not, I've just pointed out how little sense it made.

My mother used to do this. She made sure that my DD was always right next to her. Now, my situation is likely different from yours in that I never spoke up because she has NPD (Narcissistic Personality Disorder) and I basically couldn't bear her wrath. Tried speaking up to my father, but he lives his life tiptoing around her and never standing up for the smallest thing. No help.

All this to say that I finally realized when DD was eight that my mother had hijacked countless special moments and holidays and that I'd been too scared to speak up in the moment. Given my situation, I had to cut all contact with my mother in order to reclaim my own chance at motherhood (and my mental health). I too was left out of so many special photos and to this day the number of photos with my mother and DD (especially on DD's birthday, Christmas, etc) outnumbers the ones of me with DD by about fifty-fold. Maybe more.

You can't take these moments back, OP. This was your son's birthday. Don't let another special day be on someone else's terms. It may be their house, but it's your child. If your MIL is a nice person then simply say that you'd like to sit next to your child from now on. You shouldn't have to say more than that, and if you do, then you have a bigger problem.

If your son's birthday was just yesterday, I'd go out and get a cupcake and make a special smaller family event today and make sure that you are in the video when you sing to him. Take back the memories. I wish I had.

YANBU OP, but I don't know why you haven't just moved the place names, especially for a birthday meal. Do it next time (and every time, if necessary) and don't give it another thought.

Balls. OP presumably has no language barrier with her husband, who has told her they can easily swap.places.
Job done, nothing to see here.

I’d swap with your dh and keep doing it till they get the point. I think they are doing it deliberately so they get their son and his son to themselves but at your upset so it’s unacceptable

Solution 2: teach Dc always to throw food when he’s with his Dad! 🤣

That was my thought.

To all the posters saying "Use your words or the like". There is a language barrier. The in-laws and the husband may be French, but OP is not and they do not live in France. Learning the language would be useful, but it takes many years to become fluent enough to stand up for yourself and to understand all the nuances of passive aggressive communication. In the mean time OP would still have to put up with this nonsense, unless she is prepared to be rude and physically mark her space. It may need to come to that, but it certainly won´t improve the relationship with the in-laws the mean time, or with her husband.

To all the posters saying that the in-laws are "trying to give her a break", I would agree, were it nor for the fact that they seat her not just "away", but as far away from her son as the table will allow. This does not send the message that it's for her benefit, but rather that they find her a nuisance to be tolerated since she is the child's mom. This forum is full of examples of women being treated as mere vessels for grandchildren, but are clearly not liked, respected or welcome in the family. Not included her in the photos is another red flag.

Finally, why is the husband not stepping in to intervene? They are his blood relatives, he knows it upsets OP and he is fluent in French. He could have remedied the situation, especially around the birthday cake and the photos to make sure OP was included, but he couldn't be bothered. Which says a lot about him too.

I'm with @ragandbonewoman

Out of interest, how are they the rest of the time?

And did they get a photo of you with Dc and the cake?